In Monsters, Inc., when Mike Wazowski and Sulley get banished to the wasteland in the Himalayas, the Yeti greets them and makes them feel comfortable in his cave. He also shows himself to be a comedian, such as when he mentions about his friend Bigfoot, who has called himself "King Itchy." When he mentions something about a local village, Sulley, still wanting to help the human child he has accidentally brought into the Monster World, suddenly demands the Yeti to tell if there are any kids in that village so that he will be able to sneak back into the Monster World. However, the Yeti warns Sulley against going out in a blizzard, but Sulley does so anyway.
The Yeti is last seen calling to Sulley that he has made more snow cones (after the lemon ones had been used up as a tossing weapon by Mike), but Sulley either ignores him or is unable to hear him due to speeding down the hill on his makeshift sled.
The Yeti appeared at the end of the prequel Monsters University as a Monsters, Inc. employee who introduces Mike and Sulley (then new arrivals) to their jobs as mail sorters. He tells them not to mess with the mail or peek into them, as such acts are punishable by banishment, implying this was the reason he was banished later on.
It is revealed in Monsters University that the Yeti was actually once a mail sorter at the Monsters, Inc. factory, but was banished to the Himalayas for accidentally messing up his job by tampering with the mail. This is also an homage to his voice actor's role as Cliff Clavin the mailman in Cheers.