Looking for a video game.

There was Video game I used to play that I can remember back from 2015-2018 that was at its highest peak, I remember people like markiplier and jacksepticeye playing it aswell, I know it was semi popular and I know a lot of people used to watch these YouTubers above, the main detail I remember is that there was a code in the game called “GUTS” like a combination I think or maybe just a normal code. I know many people watch them so maybe someone could help me and jock their memory. Thanks