On Thursday, Mackie detailed the fantasy football league he competes in with other Avengers stars. The actor recently finished second to last with Chris Pratt winning the season.
"It's a split. I mean Chris Evans talks a lot of trash. Paul Rudd talks intellectual trash, which is confusing because you don't know if he's insulting you, but you feel like it's a diss somewhere in there," Mackie said when asked who the biggest trash talker is.
"So he's the guy you want to fight. You know, you can talk back to Chris, but Paul it's like nah," Mackie continued, before joking about having to Google the words in Rudd's insults.
Mackie and Fallon also played a few rounds of Hey Robot, a password-like game where the pair took turns asking a smart speaker questions in an attempt to get it to say a random word.
Fallon won the game after successfully getting the smart speaker to say rectangle and zombie.
Mackie next stars in sci-fi action film Outside the Wire as an android super solider. The film comes to Netflix on Friday.