Grease that burns is actually in 3.5 as a level 2 spell. It disappears after you set it on fire and doing damage to everyone in it. One of the later supplements. Can't remember the name offhand because I have always felt that it was retarded for +1 spell level for an advantage and a drawback.
I didn't know about it prior, but I looked it up and I believe you're talking about
Incendiary Slime. I would consider that spell completely superfluous, myself - they should've just revised Grease and included some "alternative uses", in the same way they provided inventive uses for Prestidigitation in one of the 3.5 books too.
And I don't know where you got the part that you ignore parts of spell description as you like, rule lawyer or not.
That is not a retarded rules lawyer, that is just a retart. If anyone tried to pull this kind of shit at my table, he would never be invited to play again.
The interpretation hinges not on ignoring the text, but disregarding its relevance to the effect of the spell in terms of systemics. It's "flavour-text", much like how some spells say things like
"A bolt of blinding white light is sent from your finger-tips", and
then goes on to explain the actual effects of that, in where the bolt of white light doesn't actually blind or disorient anyone, but maybe just causes electrical damage in a straight line or maybe sets fire to the area, etc. Don't read it like a reasonable human being that expects context to matter, read it like
an autist a robot following a programmed flow-chart. To this kind of "person", Grease can take down flying enemies because they are in "the area", Stinking Cloud affects non-sentient Plants and has nothing to do with stinking or clouds, and fire spells can't set fire to anything because it doesn't explicitly say that they do (I've legit had that last conversation with someone, regarding WFRP2 Pyromancy).
This is also part of why I dislike the idea of disregarding context and expecting a 1:1 parity between a PnP and a CRPG: In a PnP, you have the GM to arbitrate based on what "makes sense", regardless of what what the rules say, whereas in a CRPG, it's all much like a mathematical formula completely divorced from reality/verisimilitude. One great example of this is actually how crazy powerful Grease is in almost every D&D-based (and I include PF in this) CRPG due to how it's written, whereas in a PnP...? The enemies? Many of them would've just fucking jumped over it, unless it's a 10-foot wiide corridor (and in some cases, even then).