The Tavern

Oil Spray - Level 4 - Hexes/Poison/Conj - You spray out a cone of slippery sticky oil that gets everywhere. Does (small, spellpower-dependent) direct damage on contact with enemies and can blind and/or confuse enemies who don't have rPois. Additionally all corporeal enemies (Not ghosts, Ooze, etc.) hit are temporarily given the Oily debuff, which makes the invisible visible and gets replaced with Sticky Flame if they are hit with any fire hit. Lastly the slippery oil coats the ground for a few turns causing enemies to slip around (take longer to move, fumble attacks). Any strong enough fire spell (B.Fire, B.Lightning, Fireball) can ignite the oil causing flaming clouds to appear above it and timing out the floor effect faster; ignite poison also replaces the oil with flaming clouds.

Meant to combine the effects of Mephritic Cloud, Leda's Liquefaction and Dazzling Spray (and replace those spells for the most part). Also meant to further solidify the connection/synergy between fire and poison spell schools. Found in Young Poisoner's Handbook, Book of Debilitation, and Book of Maledictions.

1. You don't mention what sort of area is hit with it (it seems like maybe it's meant to be a cone, but it might effect all of LOS or just a line, or multiple rays ending at monsters like dazzling spray, I dunno)
2. You don't mention range.
3. This is a pretty awkwardly complicated spell It has 4 direct effects (damage, confuse, blind, and new "oily" debuff (does it do anything other than possibly turn into sticky flame?)) 1 area effect (sounds like maybe the effects of water minus the move delay(?) is it a cloud-type effect or a new terrain, can oil and water mix? ) and then a host of interactions with fire spells (including ignite poison) complicated spells generally speaking are a harder sell then simple ones.
4. You mention combining some spells, but it's not entirely clear, is it your intention/preference to remove those spells while adding this one?

Bringing back ranged Sticky Flame and buffing it is a pretty hilarious idea.