inspiration for my creature's transformation

heres some of the cute creatures from films and animations i've found that snap and turn into something evil. I think i'm gonna go down this route, create a sidekick or small creature that's so damn cute then something happens maybe they get angry or they eat a certain food, then BAM!
A totally different side to the character is seen. (I've been thinking also about maybe having a cute creature which morphs into there proper form maybe a human or a bigger beast or an alien.)

Hellboy 2 - The toothfairies

 

the pixies are a great example of a transforming cute creature there're drawn simply and transform with facial reactions and teeth. It doesn't really take alot to transform i think. Unless your the hulk, then your fucked.

Galaxy Quest - Blue demon babies

 Earthworm Jim - Peter puppy

The incredibles - Jack Jack

Cats vs Dogs

Russian kitty