Dooming a player is an immediate effect. Each Horseman type will apply a different effect when dooming. When a Horseman attempts to doom another Horseman, it fails: the two Horsemen unite, joining a shared channel. Doomed players are informed that they have been doomed, but not which Horseman doomed them. Doomed players can be doomed again by the same or a different Horseman. Dooming and its accompanying effect will immediately disappear when no Horsemen remain. When all remaining Horsemen are united and all remaining players doomed, Doomsday is unleashed: Each living Horseman turns into an Apocalyptic Horseman, with the ability to attack a player each night.