I have that sometimes.
One time I tried chewing some salvia extract instead of smoking it and instead of zooming down to the salvia dimension I dissociated pretty heavily and the world and all the people around me became 2 dimensional like everything was just the backdrop for a play. I just had this overwhelming feeling like I could just grab reality and rip it away and the real universe and reality would be behind it. It was a bit unsettling because it felt like there was something or multiple somethings right behind it watching me waiting for me to do something. It didn't really last long, a half hour at most but it's still, to this day, one of the strangest experiences I've ever had in my life and I'll never forget that feeling of unreality and being a flat 2 dimensional being in some kind of wider higher dimensional universe.
