Can Polymorph Potion be used to prevent your opponent from getting a level

[Eben]

Originally Posted by Flemroid

Does this also mean that if a monster instantly defeated that would give the munchkin level 10 you can wander in a monster that he/she would have to defeat in order to get the level?

If the munchkin can wander in another monster for the needed level and can defeat said monster, then yes, you could still win. You still don't get a level for the polly-ed monster.