Originally Posted by mrfuji3
Originally Posted by Grudgebearer
You are aware that most lubricating oils even those derived from petroleum, are combustible, but not volatile, right
No I wasn't, but that doesn't really change my response. The grease spell doesn't specify that it can't be set on fire; thus my wizard has based his Grease Spell off of one of those lubricating oils, even those derived from petroleum, that are volatile.

Plus, unless you ignite grease on the same turn that you cast it, it's unlikely that any enemies will still be in it as any creature with a speed of >=20 ft can freely walk out on their turn. It won't result in overpowered play, so why not let players do it?

It's a level 1 spell, and the fact that it doesn't say that it can be set on fire, tells you that it can't be according to the rules. Otherwise you have a level 1 spell that is far more powerful that its casting level.