I once tried to do a Mash-Up with VeggieTales & 3-2-1 Penguins. It didn't turn out so well, though this line here worked completely genius:
"It's A Lie! The Monster Is A Lie!" - Alfred
"Oh My! Well, how do I stop it?" - LarryBoy
"We scream, Like this: AHHHHH!!!" Zidgel