Phil

Phil (also known as Pajama Ninja) first appears in the episode, "City of Thieves" when he steals the basket and glasses from the Cyclops. His pajamas are then stolen by Rock Wall Thief, and his glasses are stolen by a goblin. He is then punched by Jake. Phil wears a special pair of underpants that can lock, presumably so that they cannot be stolen. He later appears as one of the Naked Old People in "Blood Under the Skin." He has the voice of an older man in this episode.

He is also seen attending Wizard Battle in the episode of the same name as part of the audience. He can be seen crying beside Lumpy Space Princess.

He attends Finn and Jake's holiday event in "Holly Jolly Secrets Part II" and for the first time he was referred to by name as "Phil." In the same episode, Phil wears a pair of puffy pants with Christmas Trees on them. He doesn't wear a sweater, but he wears a scarf.

He also appeared in "King Worm," popping up behind Peppermint Butler then saying, "Satori!" and throwing a spoon at Finn in Finn's dream.

A little person version of Phil was seen in the dance party in "All the Little People ."

Quotes
"My jammies!"

"My glasses!"

"My most private parts! Peeped by a boy!"

"Satori!"

Trivia

 * His appearance is based on Phil Rynda, (former) Lead Character Designer on the Adventure Time staff. (That is why his face resembles a PHIL FACE, although the character Phil usually does not make the actual PHIL FACE expression, which involves and open mouth curled up at the corners and arched eyebrows.)
 * Phil appears to look human; it's quite surprising that Finn did not notice this, considering he believes that he is the only human left in the Land of Ooo. Phil is more likely just a humanoid.

Videos
My Jammies! My Glasses! - Adventure Time