Katie Cook is a professional cartoonist with a strong sense of cuteness. When she's not making Fraggle Rock comics or drawing the Avengers as cats, she's working on her own webcomic, Gronk, about a sweet little monster and the geeky composer whose life she turns upside down.

If the Internet was built so that people could post pictures of their cats, then Twitter was built for this. Artists came up with their best kitty-Marvel mashups and tweeted the adorable results.