Anpu

Anp (アンプ, Anpu) is a cat who frequently loiters in front of the Saiki House. He was saved by Kusuo when he got trapped between two buildings and got attached to him despite Kusuo's continuous rejections.

Background
After being saved by Kusuo, he starts to visit his house in an effort win over Kusuo's affection. He once got Kusuo, who was disguised as a cat known as Psi, to aid him in trying to woo a female cat Pushi. Later on, Kusuo pets him after Anpu saved him by chasing away a cockroach.

Trivia

 * His name is a pun on Anpusi (アンプシー, Animal-Psi) the ability to psychically communicate with animals.
 * Kuniharu was the one who named him.
 * Called "Amp" in the Netflix subtitles.
 * The symbol Ψ is on his forehead.