Uchurei!

Uchurei! (ウチュレイ！, lit. "Space Ghost!") is a 12 episode anime series by Studio Robot.

Plot
The "summer supernatural teen comedy" revolves around an ordinary high school boy named Takashi who ends up living with a space alien's spirit (uchūjin no yūrei) after a strange incident. He names the creature "Uchurei" and plans to keep it as a pet, but becomes possessed by it.