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 of 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."
You're a sociopath.
- The Cosmic Owl's design is based on the lighting above a urinal at Cartoon Network Studios.
- His voice resembles the voice of Dr. Phil McGraw.
- The Cosmic Owl may also be a psychopomp who guides souls to the Land of the Dead, since he is so important in croak dreams.