Before we watched this video of Robin Williams palling around with Koko, a gorilla who is fluent in American Sign Language, we assumed it would be nothing but the comedian cracking wise about bananas. But, surprisingly, the actor’s meeting with Koko is a touching reminder of how similar we are to our ape cousins.

During their playdate, Koko repeatedly flashed the “tickle” sign and Williams was more than happy to oblige. The gentle beast also tried on Williams’ glasses, and at one point grabbed his wallet and took a look at his ID. (Perhaps she wanted to make sure he was really hanging out with the star of ‘Patch Adams.’)

Williams called his experience with Koko “mind altering.” When you take a look at the video of their encounter below, you’ll see what he means