The Tavern

So I've noticed that most Cj I spectate never seem to learn Fulminant Prism, and even when they do they typically never bother to cast it. Usually when I ask them why, they tell me they tried it once and thought it sucked. Well, I'm here to (hopefully) set the record straight.

Fulminant Prism is a level 4 Conjurations/Hex spell that creates a prism of destructive energy at a smite-targeted location. After 20 auts (typically 2 turns), the prism explodes dealing unavoidable non-elemental damage to everything inside a 5x5 radius.

Pros:

Giant area of effect. It's only a step lower than firestorm (5x5 as opposed to 6x6), while being several times cheaper and easier to learn. The huge area it covers is especially good when you consider that it has...
Massive damage for a level 4 spell, easily outdamaging most level 5 spells, and even some level 6 spells when you take the huge AOE into consideration. This also makes the spell...
Very mana efficient, it does huge damage over a wide area for only a modest cost of 4 MP. If you're with Vehumet, casting this spell is almost like channeling magic in many cases.
Effective against both single targets and groups. While obviously this spell is far more effective against large groups of enemies, it still has a gigantic amount of damage for a level 4 spell, making it also effective against big, single target threats.
Smite targeted, this allows you to place the explosions in the most optimal position and get the most value out of the spell.
Undodgeable. Since the spell is considered an explosion, it completely bypasses EV, meaning you never have to worry about the spell missing and your MP being wasted.
Can hit things around corners. This is very effective against dangerous ranged targets that can't chase, such as Oklob plants and electric eels.
Effective against all targets. Because it does not deal damage through an element, it is effective against all targets equally, and since it ignores EV the only thing enemies can use to mitigate damage is AC.
Absurdly destructive early on. Once you get Fulminant Prism castable, it typically already has enough spellpower to destroy most early game threats in a single cast (orc packs are a joke with this spell), and it deals with most big scary things in only two or three casts.
Scales very well, the damage never stops being relevant in a 3 rune game, maybe perhaps not in extended (I haven't tried it in extended, so I can't really say).
Very versatile. It's not just for blowing dudes up, it can also be used to block choke points and stop projectiles. Placing one in between you and the enemy also stops non smite-targeted spells.
Extremely fun to use. This is perhaps subjective, but it's definitely one of the more unique spells in this game, and the amount of positioning it requires goes some ways to make even popcorn fights somewhat interesting.

Cons:

Requires you to level up hexes. I would assume this is perhaps the biggest downside and/or turnoff to most people. Leveling up hexes on a conjurer is somewhat unintuitive, especially early on when there isn't much XP to shift around and it can be a problem if your race has a terrible hex aptitude.
Has a 2 turn (20 aut) delay before detonation. This is typically irrelevant as long as you have room to kite backwards while you wait for the detonation, but if you have nowhere to move it can sometimes cause problems.
Somewhat ineffective against targets that are significantly faster than you. It does big damage, but if you're attacked by something such as a black mamba or a crocodile that's swimming through water, they will typically reach you and get a hit off before it detonates. This is mostly irrelevant against enemies that are only slightly faster, such as spiny frogs or ugly things.
Unreliable against blinking targets. Once again, it still does significant damage, but enemies that blink are capable of avoiding your damage entirely by simply blinking out of the blast radius before it detonates.
Somewhat dangerous to use against strong ranged threats. Enemies such as centaurs and yaktaurs are dangerous and have the ability to deal significant damage to you before your first prism detonates. While the prism can easily wipe out a pack of such enemies, it's important to have an alternate spell to deal with these threats if you're caught in a bad situation against them.
Requires some existing knowledge about enemies, and good positioning and forethought to be most effective. To get the most out of this spell, you need to really think about where you're going to place the prism and how you're going to act in the turns leading up to the detonation. You need to consider how to place prisms in such a way that two of them will be able to hit your targets, without placing them inside of each other's AOE. You need to know how fast enemies move and where they will end up in two turns, and place the prisms and move to manipulate the enemies accordingly.
Extremely dangerous if you're not careful. This spell does big, undodgeable, unresistable damage in a huge area of effect. You do not receive any warnings or prompts if you're inside a prisms AOE. It is fairly easy to damage yourself accidentally with this spell if you're playing fast or simply not paying attention, and this can be very devastating especially early on when you don't have much health. It's not unreasonable to expect to lose 50% - 70% of your health from a poorly placed prism.

This spell seems to be very misunderstood. It is absolutely absurd and I wouldn't hesitate to call it overpowered. It's relevant all game long, from the moment you learn it until you enter Zot, it's always worth casting at one point or another. It completely obliterates packs of weak enemies, and takes out tough targets almost as fast. If your race has good aptitudes (deep elves are godlike prism users), it isn't unusual to be able to one-shot early tough things when they start showing up, such as ogres and orc warriors. Even if they don't die in one hit, they usually go down with a follow up prism. This remains true for most of the game, and it's not far stretched to say that you can carry yourself all the way through lair, both lair branches, and some of vaults using just this spell alone and nothing else. With good skill investment, it's not unusual to be able to one-shot hydras by the time you get done with lair, and later on you can wipe out groups of monsters such as a pack of deep trolls with only two or three casts (if you get a generous damage roll, it's entirely possible to kill them all in one prism). It has the highest damage output of any of the spells in the starting book, and the damage doesn't start weakening really until you reach vaults, at which point it still remains an amazing AOE option against groups. Eventually you want to learn some sort of good damage bolt spell to help against late game high HP enemies such as stone giants or titans, but even at that point in the game the damage the prism does is still very relevant.

Even if it wasn't an AOE explosion and was just a single target spell like magic dart, the damage is still very high for its level, higher than any other level 4 spell. Mystic blast is very weak compared to this spell, and I very rarely find myself in a situation where I feel like mystic blast would be a better option than a prism. The fact that it IS AOE means that if you catch a group of enemies with it (which isn't hard, the AOE is HUGE), it will easily outdamage most level 5 spells, and if you catch a lot of enemies with it, it easily outdamages level 6 bolts. Indeed, it isn't uncommon for the prism to be a better damage option than a level 6 bolt spell, even later in the game.

Here is a very short video I made showing how absurd this spell is early on, I recommend watching it if you still don't believe me:
https://www.youtube.com/watch?v=-Ll8_g3pSgk

There are many ways to place prisms to achieve desired effects. Here are some simple essentials, they might be obvious but I figured I'd include them in this post. There are other ways to manipulate prisms to get the most effectiveness out of them, but I'll leave that up to you guys to figure out as it's part of the fun.

Damaging a single target or a group of enemies with multiple prisms

Damaging a target adjacent to you

Damaging a target adjacent to you with multiple prisms

EDIT: One thing that I didn't mention (but I should have!) is that enemies treat the prism like plants; they only attack them if they absolutely have to in order to get to you, otherwise they completely ignore them and walk around them whenever possible.

A++ for the animated gifs!

I always use FR all the way through the game. And thanks for the neat gifs!

The switch to square LOS changed FP's explosion; I'm not sure if that made FP easier or harder to use.

In circle LOS, it exploded as

Code:: xxx xxxxx xxoxx xxxxx xxx

Who is "you"? I am noticing a lot of topics with "you" on the title. Is this clickbait?

Good post. My main issues with it are that it is often difficult to affect multiple targets reliably, and there is a chance you could get hit (eg you can't move where you thought you could).

And most importantly it is battle magic, which is far more tedious than melee and not necessary for a solid 15 rune win.

MrPlanck wrote:Good post. My main issues with it are that it is often difficult to affect multiple targets reliably, and there is a chance you could get hit (eg you can't move where you thought you could).

Yea, unlike most straight-forward damage spells, the prism really does take a bit of practice to be able to use. Once you get it down though (it doesn't take very long!), it's invaluable and you'll be able to know where you need to place your prism to hit everyone while also keeping yourself safe just by taking a quick glance at your situation.

Well it's tedious even for battle magic which is saying something. I think a lot of people skip it because battle sphere and dart annihilate things and are less noisy, not quite as tedious, and uses hexes. But since I usually go sif as a Cj I memorize it for packs of enemies and ditch it later.

MrPlanck wrote:Good post. My main issues with it are that it is often difficult to affect multiple targets reliably, and there is a chance you could get hit (eg you can't move where you thought you could).

And most importantly it is battle magic, which is far more tedious than melee and not necessary for a solid 15 rune win.

Battle magic being tedious is subjective. Some people (ie myself) actually find melee very boring and prefer the positioning casters require. If you don't like casters then just don't play them instead of complaining that you don't like that play style.

ydeve wrote:Battle magic being tedious is subjective. Some people (ie myself) actually find melee very boring and prefer the positioning casters require. If you don't like casters then just don't play them instead of complaining that you don't like that play style.

My problem with melee is that sometimes it's so strong that I just end up holding tab through 80% of the game, and then when I actually get into a situation that I can't tab through I just instantly splat because I'm hardly paying attention. Using magic actually makes you slow down and take each fight at a nice steady pace, you can't just turn your brain off and hold O + Tab and watch the game play itself.

One other downside is that it's fairly loud. You need to be prepared for more and more opponents wandering in. With enough mana reserve, it's not bad, but early on it's easy to run out and find yourself in more of a target rich environment than you really want.

I know I need to use it more than I do. My current SpEn has learned it, but has only cast it once. being a sneaky little stabber, I'm just hesitant to make all that noise.

BTW, great article, Thanks!

This has opened my eyes to the awesomness of FulPrism, thanks a lot for the well written (and illustrated!) article.

Code:: [nrune=15;dam=88] MorganLeah the Conqueror (L27 MfAr of Kikubaaqudgha), killed by an exploding fulminant prism (created by Schuwk) on D:13 (hangedman_vaults_entry_quadrant_bands) on 2015-03-21 04:18:32, with 1311326 points after 89209 turns and 6:57:26.

This came after a tomb Orbrun.

Is that a player ghost or a randomly generated panlord? I didn't think any enemies in the game could cast fulminant prism. Nevermind, I'm like 99% sure it's a player ghost, I don't know why I thought it was something else...

ydeve wrote:
MrPlanck wrote:Good post. My main issues with it are that it is often difficult to affect multiple targets reliably, and there is a chance you could get hit (eg you can't move where you thought you could).

And most importantly it is battle magic, which is far more tedious than melee and not necessary for a solid 15 rune win.

Battle magic being tedious is subjective. Some people (ie myself) actually find melee very boring and prefer the positioning casters require. If you don't like casters then just don't play them instead of complaining that you don't like that play style.

Of course it's subjective. That's why I said "My" instead of "Our". All sorts of ways to enjoy the game.

"Schuwk" sounds very panlord-ey, and these definitely do have fulminant prisms: http://s-z.org/neil/git/?p=crawl.git;a=commit;h=7c202e2f61a564b33ec996e763e9c8799dcdf7d4

Also worth noting: you can place a prism between you and, say, Erolcha, to block banishment and other hexes. In some circumstances, the prism can also be used as a poor man's summon small mammals to pad an escape.

Yea, I mentioned that in the OP, it's pretty useful to be able to block spells or block corridors like that.

One thing that I didn't mention (but I should have!) is that enemies treat the prism like plants; they only attack them if they absolutely have to in order to get to you, otherwise the completely ignore them and walk around them whenever possible.

Oh sorry, I must have skimmed that bit.

Laraso wrote:Yea, I mentioned that in the OP, it's pretty useful to be able to block spells or block corridors like that.

One thing that I didn't mention (but I should have!) is that enemies treat the prism like plants; they only attack them if they absolutely have to in order to get to you, otherwise the completely ignore them and walk around them whenever possible.

Last I checked, I thought monsters treated prisms like summoned critters and were perfectly happy to smash your prism early, even when it wasn't preventing them from getting to you.

I remember it kind of being that way when the spell was first added, but playing in trunk they seem to just pretend like it doesn't even exist.

I'm pretty sure I've seen monsters attack prisms when they could have avoided them, but I'm not sure how recently I've seen it. Sounds like it's time to play a conjurer or two to test it out...

In recent versions of the game, I regularly see Centaurs go out of their way to move to the side of the prism so they have an unobstructed firing path. You can place one directly in front of an orc warrior, and he'll just walk around it if there's room, pretty much 100% of the time. You can place one directly inside a huge pack of enemies, and 90% of the time it will survive and detonate at full power.

Yeah, a quick series of tests show orcs walking right past my prisms. I didn't set any up completely blocking a path, but they will step around prisms instead of attacking them.

Oh my. My DrCj just found a book shop on D:4 with a book of Power, book of Unlife, Akashic Record, and a Necronomicon. Nice selection of spells, once he finds a bit more cash.

Just took out Sigmund with 2 FPs, while he was invisible, which is another nice use of FP. You can usually make a good enough guess where an invisible foe will be so that you can hit it with an FP.

Killing Sigmund bumped up my hexes by 2 levels, and got me to experience level 7, whence my scales turned purple. This throwaway character to test out FP is turning into something that has distinct possibilities. He started out by finding both a +1 pair of boots of flying and a +2 hat on the floor of D:1.

I believe monsters started walking around, rather than attacking, avoidable prisms once they were marked as no-XP (0.17-a0-1237-g21d49c6). Now they count "firewood", so monsters react to them same as plants, only attacking if there is nowhere else to move (in a hallway, for example).

The change is definitely an improvement for the usability of the spell, but maybe it's too good now.

neil wrote:I believe monsters started walking around, rather than attacking, avoidable prisms once they were marked as no-XP (0.17-a0-1237-g21d49c6). Now they count "firewood", so monsters react to them same as plants, only attacking if there is nowhere else to move (in a hallway, for example).

The change is definitely an improvement for the usability of the spell, but maybe it's too good now.

I forgot that monsters also attacked the prisms, which is another, and perhaps primary, reason I stopped using the spell. I have not used it since this change, and now I'll def. give it another try. Thanks for this info. edit- and thanks Laraso for an excellent op.

neil wrote:The change is definitely an improvement for the usability of the spell, but maybe it's too good now.

I definitely believe that this spell is quite a bit too powerful, the damage needs to be taken down a couple notches.

That being said, it is also tons of fun to use, so I hope some sort of useable middle ground can be reached, I'd hate for it to be nerfed into obscurity once again.

One more use which hasn't been mentioned yet. You can use the prism to block a hostile OOD.

I think you can also use it as a sugar substitute in pancakes. Might need some testing.

ydeve wrote:Some people (ie myself) actually find melee very boring and prefer the positioning casters require.

You mean literally anywhere within like 6 squares that won't immediately get you killed right

ajon wrote:I think you can also use it as a sugar substitute in pancakes. Might need some testing.

Everyone, do not try this. For one thing, it absolutely requires the eggs as a binder to keep the prisms stable. if you make your pancake without eggs, the prisms will just explode in the mix, requiring extensive kitchen remodelling and potential hospitalisation.

Second, even if you do eggs, their binding magic is limited. On exposure to stomach acid, the prisms will begin to once again destabilise. The result is somewhat akin to that of sugar-free gummy bears, but much more dangerous. I was scrubbing the bathroom ceiling for weeks!

TL;DR: Fulminant Prism in baked goods: not even once.

I just figured I'd add some average damage numbers to back up the damage claims here.

Lvl 5: Iskenderun's Battlesphere (per shot)

Code:: 7+0.09*Power

Lvl 4: Fulminant Prism

Code:: 10.5+0.263*Power

Lvl 5: Fireball

Code:: 6.5+0.25*Power

Lvl 4 (single spell): IMB

Code:: 7+0.16*Power

Lvl 6: Bolt of Fire

Code:: 12+0.333*Power

40 is quite reasonable power to hold them at through the midgame, so that gives average damages of:

Code:: Iskenderun's Battlesphere (per shot): 10.6 Fulminant Prism: 21 Fireball: 16.5 IMB: 13.4 Bolt of Fire: 25

The one other important metric here is mana-efficiency (which prism clearly wins vs all but IB). For IB it's trickier. Assuming triggering IB with magic dart at a single enemy, the break even point for mana efficiency is:

Code:: 0AC target: 2.7 darts 5AC target: ~5 darts

But I'd expect FP to have some advantage over the direct-fire type weapons, since it requires guessing where the opponent will be (not generally too hard), and a 20 aut delay, instead of firing where the enemy is right now, and doing damage right now. Damage right now is worth more than possible damage 20 auts from now.

It would appear that practice makes good placement second nature, reducing that disadvantage vs. direct damage. Also, as an explosion it ignores EV, which can be a significant benefit. And even more, there are the blocking benefits of the prism.

MainiacJoe wrote:Also, as an explosion it ignores EV

Question: Does AC apply against the explosion damage three times, once, or not at all?

BugHunter wrote:But I'd expect FP to have some advantage over the direct-fire type weapons, since it requires guessing where the opponent will be (not generally too hard), and a 20 aut delay, instead of firing where the enemy is right now, and doing damage right now. Damage right now is worth more than possible damage 20 auts from now.

The only time "do damage right now" is superior is if a scary ranged threat or a scary fast threat (think centaurs / executioners) is in view. Against like 80% of the enemies in this game, the delay is completely irrelevant as you can just back up two spaces to detonate the prisms.

MainiacJoe wrote:Question: Does AC apply against the explosion damage three times, once, or not at all?

I'm pretty sure it only applies once, considering that you can one-shot orc warriors with it early on in the game.

byrel wrote:The one other important metric here is mana-efficiency (which prism clearly wins vs all but IB). For IB it's trickier. Assuming triggering IB with magic dart at a single enemy, the break even point for mana efficiency is:
Code:
0AC target: 2.7 darts 5AC target: ~5 darts

True, but if you're fighting more than a single enemy at a time, the prism still wins out in mana efficiency.

I adore Fulm Prism. I just had a very successful run - until I was a freaking moron vs. TRJ - with a spriggan hexer and fulm prism, and a whole lotta kiting.

With fulm pris and kiting you not only get the benefit of spriggan speed, but you can use the fulm pris to slow down pursuers. Dropping it in a mobs path as it chases you means it will spend auts moving around it, as long as it has a path to do so. If it doesn't it'll destroy the prism.

I've also had great success with hybrids or particularly durable casters who can tank a bit. If you're facing a group and can back into a protected area, like:

##gg
@gggX
##gg

Dropping a prism at X will nail all the mobs (g) while you take hits from only one of them. Too. Much. Fun.

I'll admit that I've always skipped this in the past as a Cj. The Hexes requirement was a deterrent, as I would always focus on getting Battlesphere up ASAP. That requires Charms, but you're more likely to want Charms later anyway for the powerful utility spells it opens up. I think in this respect the Hexes requirement helps balance out what would otherwise be over-powered, though it's unfortunate that it discourages people from even giving the spell a fair shake.

I'll have to give it a try the next time I play Cj. It sounds like the way you would use this is by getting it in lieu of Battlesphere (at least for the early/mid game.) The damage numbers look impressive (especially when you consider the size of the AOE) and the timing aspect makes it interesting.

BugHunter wrote:But I'd expect FP to have some advantage over the direct-fire type weapons, since it requires guessing where the opponent will be (not generally too hard), and a 20 aut delay, instead of firing where the enemy is right now, and doing damage right now. Damage right now is worth more than possible damage 20 auts from now.

You are correct. Future value must be discounted to find present value. This is the foundation of the theory of interest.

Assuming Fireball is representative of a comparable "damage right now" spell at 16.5 damage, the implied interest rate on damage in DCSS is 1.205% per aut (continuously compounded).

The most recent 3-rune melee win I found took 906,790 auts. Let's take that as reasonably representative of an average non-speedrun game. If you start with a long sword, dealing on average 0.5 damage per aut, by the end of the game you should deal 1.433 x 10^4745 damage per aut on average.

Since the average character deals less than 1.433 x 10^4745 damage per aut by the end of the game, and everyone knows o-tab-o-tab is the optimal way to play Crawl, we can conclude that Gozag must strongly appreciate the use of Fulminant Prism. I have filed a bug report accordingly.

One more average damage stat: Searing Ray (level 2 single school), 40 spell power, zaps 1/2/3/4

Code:: 7/7/11/14.6

Yes, the last shot out-performs IMB. The Cj spell book is damn good.

Searing Ray is also godly. Pretty much melts almost any early uniques you find, except maybe Grinder if he paralyzes you.

Searing Ray is far better than Dazzling Spray in the Book of Conjurations.

I've been playing a lot of Conjurers lately, and I'm starting to think they're mostly better off skipping Dazzling Spray entirely. Searing Ray works quite well until you hit L4 and can memorize IMB or Prism, both of which easily outclass Dazzling Spray. With Spray memorized, I only find myself using it very occasionally, mostly for the blinding effect - it's certainly useful if, say, you round a corner and run head-on into a yak pack, Spray 'em to blind and allow you to regain distance and fight singly, but it's very situational and I'd rather spend those early spell levels on more directly useful spells.

If anything, Dazzling Spray should be L2 with less damage, Searing Ray should be L3 with probably the same damage, maybe a tiny bit more.

Do FP and Battlesphere play well together or can you blow up your own sphere?

iirc they play nice

MainiacJoe wrote:Do FP and Battlesphere play well together or can you blow up your own sphere?

they're fine, though practically speaking you'll rarely have time to fire off another spell to make Battlesphere trigger before the FP goes off

Battlesphere fires at a FP victim (presumably randomly chosen), which is cool

Can someone please re-read this thread, and suggest how much of this still applies to trunk?

One big difference is that monsters no longer treat the prism as an obstacle to path around; they attack it instead.

Prism is still pretty good; it's just not as good as it was.

But battlesphere is no longer in starting book so it was indirectly buffed

In my experience the prism is only attacked regularly when placed adjacent to a monster while being between you and a monster. Experience in Hexes is not an issue, since it replaces the costs you would have put into charms with the new changes.

It's basically, a mini delayed fireball with the difference being damage resists.

Something to note about placement. The round it detonates, it's possible to walk out of the blast radius if you were on the out reaches of it's range. It still think battle sphere is more fun.

ddubois wrote:Can someone please re-read this thread, and suggest how much of this still applies to trunk?

i get the feeling it does less damage now, or the OP oversold it. it seems like solid, OK damage, but if IMB knocks an enemy into a wall, that seems to do more.

edit: i was wrong! maybe it only feels that way at low spellpower. also maybe i wasn't good at overlapping the blast radiuses yet. i'm a pretty big fan of this spell now.

The Tavern

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