Delusions are powerful, [[vision_(genshin_impact)|Vision-like]] objects produced by the Fatui. Like Visions, Delusions grant their wielders the ability to manipulate certain elements, although their power is said to exceed those of Visions, enough that they are said to make Visions look like "child's play." However, the use of a Delusion comes with heavy drawbacks, as it drains the user's life force. 

https://genshin-impact.fandom.com/wiki/Delusion