LSD

Italian Stallion's Answer:
http://answers.yahoo.com/question/index?qid=20090125204016AAN5VH9

Bodily Rearrangement (Burps):
". I personally tend to get a lot of burping when on the rise of my trips. "

Occasionally people will experience so-called Acid Indigestion on LSD, which usually manifests as minor burping without any real nausea or desire to vomit. This is often easily alleviated by loosening tight clothing and by performing relaxation exercises.

but i would just burp and it would feel awesome

but also like

fundamental

the burps were part of a material rearrangement going on in my body

mainly torso

Spilt Letters
http://www.shroomery.org/forums/showflat.php/Number/10033491

http://en.wikipedia.org/wiki/Mandala

Upon closer inspection the whole sea was filled with letters! Everywhere I saw letters of the alphabet in random patterns and combinations and spiraling in and out up and down flowing like water. I got closer and closer to the 'water' and I saw more and more letters. They got thicker and thicker. It was like those fractal things they use in math. Never ending. It felt amazing just drifting there. 
http://www.erowid.org/experiences/exp.php?ID=32307