The Cosmic Owl:
The Cosmic Owl is a mysterious creature known to the inhabitants of Ooo. Adam Muto has confirmed the Cosmic Owl has some importance in Ooo. It seems to have a country-like dialect. The owl first appeared in, "Prisoners of Love" in Ice King's Imagination Zone, after Ice King was knocked out by Finn. When Ice King contemplates why people do not like him, the Cosmic Owl answers, "You're a sociopath." The Cosmic Owl then makes an appearance in the episode, "Donny" as a drawing made by the Why-Wolf. It is stated that the Why-Wolves, if not stopped, would ravage the world and overpopulate until the Cosmic Owl would be forced to intervene by devouring them all, as is the course of nature. He appears in, "The New Frontier" at the end of Jake's "croak dream," and Finn and Jake's later conversation suggests that it's well known that the Cosmic Owl is supposed to show up in croak dreams. The owl is also featured prominently on the episode's title card. The Cosmic Owl also appears in "The Lich" where he was seen in Finn's dream on a computer monitor, indicating that Finn is in a "premonition dream." He also appeared in "Jake the Dog" visiting his friend, Prismo, in the Time Room in the Multiverse while Jake was making his wish.
Prismo:Prismo is a being who was first mentioned in "The Lich", and a main character in the episodes "Finn the Human " and "Jake the Dog " He dwells in the Time Room which is found in the center of the multiverse (He calls it his time room). Booko describes him as "almighty." This is proven true, as Prismo can grant every being in the multiverse one wish. Once the wish is granted, the wisher is transported into his/her wish-altered reality.Prismo's wishes are powerful enough to change timelines, and create or destroy worlds. However, unless worded very specifically, his wishes usually have an ironic twist. Prismo is also able to turn his wall into a "TV wall" which he can use to watch people's wish altered realities, though it is unknown whether or not he uses it frequently. Prismo can also create material items for himself and others without it counting as a wish, like food, and a hot tub, as seen in "Jake the Dog".