N, N-DMT seems to do both.

I've had experiences where you completely sink into the mystery and your sense of self is completely gone. You become the mystery, you are the mystery. The Hindus would say, you have dissolved into Brahman. It's very difficult to remember these experiences because there is no human "you" saying "hmmm...I need to remember this when I return to my human body".

The ones that people remember are where there is some sense of "self" travelling in with you. These are typically not as deep down the rabbit hole, as the first type, but are utterly insane in their own right specifically because your human mind is experiencing something it was not designed/evolved for. It really does feel like you, in a completely ordinary sense, experiencing something beyond the ability of language to describe.