Cartoon Mash-up: Do You Recognize These Guys?

Have a look at this picture. They look like someone you're probably familiar with, but also remind you of someone else. Any guesses?

I thought this was a pretty creative shirt from this website. It's a little Cheech & Chong, a little Calvin & Hobbes. How cool!
I may have to buy one of these for myself. Thought I'd share!