The 'Oh Boy, Here I Go Killing Again' meme features Krombopulos Michael, an enthusiastic Gromflomite assassin from the adult animated series Rick and Morty. First appearing in the season two episode 'Mortynight Run,' Michael utters this catchphrase with a cheerful, polite demeanor that hilariously contrasts his violent profession. The internet quickly adopted the scene as a reaction image to describe situations where someone is about to engage in a destructive, repetitive, or competitive activity with a sense of misplaced joy. It is frequently used in gaming communities to describe returning to a difficult boss or starting a new round of a shooter, as well as in more relatable contexts like starting a diet or a heavy workload.