Lying to someone specifically in a way that makes them doubt their own memory or reality. Usually a long-term thing.

For example, if you and I are alone in an elevator, and I fart…. then blame you. With only 2 of us, we both absolutely know who farted, but maybe I can convince you that it was you. Even if you 99% know that it wasn’t actually you, that 1% doubt is the start of it.

Next time something happens, I blatantly lie again and get you to 2% doubt the obvious reality. On and on until you don’t believe your own brain.