…from the September, 1969 issue
The Doclopedia #2,652
Questionable Spells: Wall Of Lard
While this spell will indeed slow to a stop any pursuer by forming a wall of cold lard that is 10′ wide X10′ high X5′ thick, that wall is highly susceptible to heat. A few torches will melt through it in a matter of minutes.
However, it must be pointed out that a Fireball spell will not only melt the entire wall instantly, it will also ignite the melted grease. That presents even more of a barrier.