What happens when a playboy engineer and timid physicist meet? A bromance. It's undeniable — Iron Man and Hulk are the coziest couple of The Avengers, and it's a relationship that's been carefully documented by Ask the Science Bros. This amazing Tumblr is dedicated to Tony Stark and Bruce Banner's many science shenanigans. It's a kind of geek camaraderie only rivaled by Breaking Bad's Walter White and Jesse Pinkman.