Pen Pen is a domesticated, tropical penguin about 2 years old. He is a minor character in Neon Genesis Evangelion, but he's very cute and often adds comic relief. Pen Pen has even learned to eat curry and drink beer!

Pen-Pen was actually part of an experiment, and when they through with him, Misato decided to take him home with her. He is often seen wondering back and fourth around Misato's apartment, lounging around, or suffering from the ill effects of his owner's futile attempts at cooking. Pen Pen wears a portable air conditioner on his back to keep him cool when he's out and about, but he also stays cool in Misato's rather large refrigerator or relaxing in her bath.

Pen Pen is reasonably intelligent and clever. Sometimes he even seems look cunning, as though he were planning something big. Pen Pen is a friend and companion to Misato, especially when she's feeling down. He gets along with everyone (especially females), and seems to take an interest in Shinji's attempts at classical music. Misato later has to leave Pen Pen with Hikari because of the potential dangers she faces.