By Meredith Lepore
Updated Jun 09, 2016 @ 11:30 am
Mark Ruffalo The Tonight Show Jimmy Fallon - Lead 2016
Credit: Andrew Lipovsky/NBC

For National Best Friends Day on Wednesday, Mark Ruffalo and Jimmy Fallon decided to put their friendship to the test with a game on the Tonight Show. The concept was simple: One person draws a question from the box then the other person guesses how the person would answer.

Now, this would be a simple game for actual best friends, but it proved to be rather difficult for Fallon and Ruffalo, who clearly didn't know each other too well.

The first question the Now You See Me 2 actor drew was "What is my favorite sandwich?" Fallon immediately thought Ruffalo was moving like a "peanut-buttery jam," but ended up guessing BLT (bacon, lettuce, and tomato). The correct answer? Peanut butter and jelly. "I feel like you don't even know me!" Ruffalo told the host.

For the next question, Fallon drew "What is my best physical asset?"

"I'm having a hard time ... because there's so many," said Ruffalo. Unfortunately, he didn't use that comment as his guess—Fallon had gone with "too many" as his answer.

At this point, the were not feeling confident. "What is my biggest fear?" was the next question, and Ruffalo wrote "Drowning in milk." And although he said this one was a shoo-in for Fallon, the host had written"To be alone in this world." Failed again.

Finally, Fallon drew, "Who is my favorite superhero?" By writing the name "HULK" out very slowly and largely Ruffalo was able to figure it the correct answer, a nod to the actor's The Avengers character. "Come on man, you know what is up!" said Fallon excitedly. Maybe they really are best friends.

Watch Fallon and Ruffalo play the Best Friends Challenge in the above video.