Monster spawner

A monster spawner is a thing that forms part of the final boss of Doom II. It periodically fires spawn cubes that each generate a monster where they land. In MAP30, these cubes can also telefrag monsters and players occupying their corresponding landing spot. In other levels, the new monster and whatever occupies its spawn spot will become stuck together. When first seen by a monster spawner, the player will hear "To win the game you must kill me, John Romero!", played distorted and backwards.

The spawner is not rendered graphically by the engine, and the only evidence of its presence to the user is that spawn cubes emerge from its location. If the flag is removed from the spawner object via DeHackEd, it will appear as a stationary Wolfenstein SS.

The spawn cubes from the spawner land at spawn spots placed around the map. The spawn spots are used in rotation, in the order they are defined in the THINGS lump in the WAD file. If there are no spawn spots, the spawn shooter still makes its "aroused" sound, but never shoots any cubes.

Monsters which may be spawned and their spawning probability:

Note: In vanilla Doom, the Demon actually has a higher spawn chance than the Imp due to the way the pseudorandom number generator is constructed.

Additionally, the rate at which cubes are fired by the spawner in the "Hurt me plenty" or higher difficulties is twice that of the "I'm too young to die" and "Hey, not too rough" skill levels.

Appearance statistics
The IWADs contain the following number of spawn shooters per skill level: