There is some evidence that seems to indicate that the humans have an evolved "built in" reaction to snake/snake like patterns: http://www.psychologicalscience.org/journals/cd/12_1/Ohman.c... As reptiles, snakes may have signified deadly threats in the environment of early mammals. We review findings suggesting that snakes remain special stimuli for humans. Intense snake fear is prevalent in both humans and other pri…
On larger doses of acid where I'm suffering immense mental agitation, the common visions are spirals, coils, and snakes.
In particular, a snake with no head, but rather attached to itself to form a hula hoop. Trying to turn over, but it can't. So it's there writhing infinitely.
The futility of it is a good representation of the abject overstimulation I'm feeling in my head. And, of course, a nice feeling of terror to go along with it.
Whenever snakey things are on the mind, I know that it was a bigger dose than I intended, and I'll soon be holding on to a panicking brain.