In "Rick And Morty", who shot "Mr. Poopybutthole" in the episode "Total Rickall"?

In the "Total Rickall" episode of "Rick and Morty," Beth Smith accidentally shoots Mr. Poopybutthole. The episode revolves around the family trying to distinguish between real family members and parasitic alien impostors who implant fake memories. Beth, believing that Mr. Poopybutthole is one of these impostors, shoots him, only to discover that he is a real family friend, and her action has real consequences. The moment becomes a memorable and unexpected twist in the episode.