Demonic Illusion: False Surroundings Technique

A genjutsu that allows one to trick others into mistaking the place they're in for another. This technique's main feature is that it can be cast over an extensive surface, therefore any and all who step into the illusion's area of effect will fall under the spell. That said, it might not work so well on people who are well-versed or otherwise skilled in genjutsu.

This technique was used by Kotetsu Hagane to trick entrants to the Chunin Exams as a test.