Pen Pen is the onsen (hot spring) penguin and he is also the pet of Misato. Although he is a penguin, but he seems to like to swim in hot spring water. He stays in the small refrigerator between Asuka's and Shinji's room. He gets a machine which is silver in color on his back and around his neck which its function is unknown. He seems very clever and can understand what Misato says. Hikari likes him very much and likes to play with him when she visits Asuka. Also, he hates Misato's cook.