The Superbad star was partying at Hollywood's Roosevelt Hotel years ago when he decided to play a trick on his friend Schmidt when he spotted him at a urinal during a trip to the toilet.
He says, "We used to play this game called earthquake, which is where you violently shake whoever is peeing at the urinal and scream out 'earthquake' as loud as you can.
"So Schmidt's peeing there and I'm really drunk and I grabbed his shoulders... and I'm screaming, 'Earthquake, earthquake,' and pee is flying all over him and everything.
"Then, all of a sudden I just hear, 'What?' and he turned around, and it's not Schmidt, it's Casey Affleck... (He was) not even bummed out, just kind of perplexed... He just goes, 'Why did you do that?'
"I'm, like, 18 and super drunk and I'm just kinda like, 'I thought you were my friend Schmidt...' He was like, 'Why would you do that to your friend?'"
The restroom encounter gave Hill a new-found respect for the actor: "He's the nicest man of all time because he was well within his moral rights to beat the crap outta me.
"I've met him since then and I was like, 'Honestly, you owe me a punch in the face if you ever want to just throw me a left hook... and I won't be upset."