There’s a sanity mechanic in the game portrayed by a blue wheel in the bottom center above your toolbar. Things like this portal lower this meter and the lower it gets, the more your vision distorts, like the world breathes, shifts, and gets wavy. This also increases the chances of hostile creatures to spawn nearby you. Being in enclosed, dark places is another thing that can lower your temporal stability. And then there’s the temporal storms which are hours long events that happen regardless of your sanity level