I have one of those players that makes DMing difficult. He's read every rulebook and has a photographic memory, instantly recalling the stats of nearly any enemy you can throw at him. So, I've learned to make... interesting... creations.
After applying the fiendish creature and monster of legend template to an advanced housecat (A creature I have named the Gigantadon because I love irony), I began thinking... what other hilarious or creative creatures have been made?
So tell me, have you run into this problem and made up a creature from a wacky combination of base monsters and templates to keep your players on their toes?