Prop Hunt is a hide-and-seek game mode where one team disguises themselves as props, and the other team hunts them down. It's a 'campaign' of observation and cunning.
Garry's Mod
Prop Hunt: The Game of Disguise
Master Prop Hunt in Garry's Mod. Learn the hide-and-seek tactics to disguise as props or hunt down hidden players in this game of observation and cunning.