>>102796739Gibbon is Jake's grandchild shown in an earlier episode with a flashforward as a kid/teen and then in the finale opening shot. One of the AT crew has a whole thing where he thinks about how Jake's descendants would have gotten around and they mostly all have some sort of special power, posting more about it on their instagram/Tumblr. Gibbon somehow getting immortality, one of the ice jewels, and the power to get rid of the powers of dogs.
Reincarnation was introduced early on where the "cosmic energy" or however it works has led to Finn being: A comet that signifies great change, primordial ooze, a butterfly, and Shoko (and even more in the comic). He is still just a human boy, but the past lives had some connection to him. The idea here is that Shermy could be a descendant or incarnation of Finn with his quirky personality, penchant for adventure/shenanigans and having an animal best friend, continung the cycle of "everything stays".
