We think it's safe to say that Mark Ruffalo and Jimmy Fallon are not BFFs.
Or at least they aren't anymore after taking this 'Best Friends Challenge' on 'The Tonight Show' last night.
Honestly, you'd think when they pitched this new bit in the writer's room they'd come up with a bit of a fallback just in case the host and guest knew nothing about each other but alas no, Fallon was left floundering in a sea in which friendship had capsized.
