The Tavern

You can't cast corona on a fire elemental because they're made of fire and thus can't be illuminated. Does this mean their EV is lowered inherently as a result of in a certain sense always being coronaed? But since they're made of fire, the illumination shouldn't affect your ability to hit them. But how do you hit them all when they're made of fire...

actually you can't cast corona on a fire elemental because they're magic immune

It does raise a question about "illuminating" making enemies easier to hit when certain enemies glow or burn, and when light of areas isn't otherwise a gameplay mechanic you have any context for

Perhaps corona should be flavored a bit differently.

"A powerful magnetic field, aflare with sparks, that betters your aim and signals the position of otherwise invisible monsters".

Ugly things, however, are specifically immune to corona because they glow. Which I believe is supposed to be reflected in their EV, although I can't verify that.

Maybe they should have a 1-tile halo effect to represent that? Does halo make you immune to corona?

Wait, ugly things actually are subject to corona, just tested it. Very ugly things too. I still think that giving fire elementals and generally shiny monsters a little halo would be cool.

So, the wiki lists a "glows" flag for some monsters; this flag was supposed to make them immune to invisibility and corona. I don't think the flag still works, although I don't know if it's just been removed from a few monsters, partially deactivated or fully removed. (M_GLOWS_LIGHT or M_GLOWS_RADIATION)