It all started when Captain America star Hayley Atwell tweeted out "Found this ugly guy" about her co-star Chris Evans.
So naturally, Chris brought up the time he "scared the crap" out of the British actress.
Even though he said he couldn't tweet the video, he put it up on YouTube. Watch the cute incident below.
Chris' video is even complete with a Captain America-shielded bird-flipping! Hayley was so startled by Chris' spook that she vowed to get him back.
"I'm gonna get you back so hard. You are ON," she wrote.
Uh-oh! You'd better watch out, Chris!