Marcel was Ross' pet Capuchin monkey on Friends Season 1. He first showed up as Ross' date for Monica's New Year’s Eve Party. Later, he ran off while Rachel was watching him, leading the the revelation that Marcel was an illegal exotic pet. Despite loving his little monkey, Marcel had to be sent to the San Diego Zoo when he reached sexual maturity and began humping every thing in sight.
Turns out that in real life, Marcel was actually a female named Katie. Katie had several other Hollywood roles including 30 Rock, the movie Bruce Almighty and she's also been spotted with Ariana Grande and Kendall Jenner. Not bad for a monkey.
Rachel: Do you think it's easy for me to see you with somebody else? Ross: You know what, hey! You're the one who ended it! Remember? Rachel: Yeah, because I was mad at you! Not because I stopped loving you!
Rachel: Daddy! Daddy listen to me! It's like all my life everyone's told me, "You're a shoe! You're a shoe! You're a shoe!" Well, what if I don't want to be a shoe? What if I wanna be a purse or a hat? No I don't want you to buy me a hat, I'm saying I am a hat. It's a metaphor Daddy! Ross: You can see where he'd have trouble.