Cramer is the stock picker guy. There is a well known "Cramer Effect" or "Cramer Bounce" where the stock peaks then drops hard.

Makes for great pump n dump if you're day trading and willing to ride

https://www.investopedia.com/terms/c/cramerbounce.asp

long-term his choices don't do well, so the Inverse Cramer basically says "do the opposite of this goober" and has solid returns (sorta; depends a lot on methodology, and the sole hedgefund playing that strategy shutdown)