Rrrmrrrmrrrfrrrmrrr or Consequences

Rrrmrrrmrrrfrrrmrrr or Consequences is an Omicronian ritual in which the submitted being must choose between two people by killing the one he or she rejects. As the Omicronians, a 14-billion-year old race, consider it to be ancient, we can assume it's actually a very old tradition. It's apparently supposed to be performed on white surfaces up in the sky.

Ndnd invoked the ritual after realizing Leela had been nagging, torturing and pushing around Lrrr, her husband, and therefore doing her job. She took everybody to White Planes in New New York so they could begin Rrrmrrrmrrrfrrrmrrr or Consequences. Lrrr was willing to shoot Leela, but Fry jumped in front of the disintegrator ray, so she didn't get shot. As a result, Ndnd was surprised Lrrr actually did value her nagging above all others, and the Omicronians went home.

Trivia

 * There's a home version.
 * The  animated TV series episode features a similar-looking ritual.
 * The name of the ritual is an allusion to the quiz show or, ultimately, the  party game.