Thing type 901, Alarm, is a type of scenery Thing seen indoors in Iron Turret Zone and many Techno Hill Zone-themed custom maps. It is an alarm that automatically spawns on the ceiling, playing a loud alarm sound effect. The Alarm is often put within a sector affected by a red colormap, for example in Techno Hill Zone Act 2 prior to v2.1. This gives the impression that the alarm emits a flooding red light in addition to the alarm sound effect, something that this Thing does not do.
