its funny how i was thinking of this this morning. also, if they were to keep having pumpkins carved naturally maybe at night a shadowy figure can rise from the insides of the pumpkin and attack the player within a range of blocks. that would be really cool, or maybe an enderman could wear the pumpkin on their heads thus having more defence but cant teleport directly at you because their vision would be limited by the pumpkin.
EDIT: Several people have posted this in other forums, but I figured I should post it here for you guys!