Mr. Meeseeks

Mr. Meeseeks (voiced by Justin Roiland (Season 1 - Season 4) is the name of all the Meeseeks summoned by activating a Mr. Meeseeks Box. The Meeseeks appear in the fifth episode of the first season, "Meeseeks and Destroy" as the titular main antagonists. They are known to inhabit planets across the universe.