GM obfuscation is a category of techniques to deceive the players for some game-related purpose.
Examples include:
- Making a die roll, even though they do no not have a particular threat in mind
- Taking aside players, even though they do not have any secret information for them
- Recruiting players to play creatures that have impersonated their PCs
- Playing dumb
- Pretending they meant to do something all along
- Uncertainty game-mastering
- Offering up red herrings
Reasons this is done include:
- To prevent players from using meta-game knowledge
- To raise tension, uncertainty, or drama
- To convey an aura of knowledge and competence
- To surprise and amuse players
- To advance the intended scenario