In the film, Anthony Mackie’s Sam Wilson plays Captain America and finds himself trying to find out who’s behind President Thaddeus Ross’ (Harrison Ford) assassination attempt. As Ross tells the new Cap to reassemble the Avengers, it’s discovered that he’s taking gamma-radiated pills, and when he’s angry, he transforms into Red Hulk.

The Marvel Cinematic Universe didn’t just need a villain worthy of Captain America. It needed a smash — and that’s what Hulks are for.