According to mythologist Joseph Campbell, snakes are symbols of death and rebirth. In his book "Psychedelic Anthropology", Allan Coult draws a distinction in serpent symbolism. He notes that snakes that are coiled are symbolic of evil. The snake outstretched is symbolic of enlightenment. This is tied into the kundalini imagery where the kundalini stuck in the root chakra is the snake when it's coiled, and when it's outstretched to the third eye where it meets the inward energy from the crown is "the goal".
I've seen snakes a handful of times on my vaporized DMT experiences. In the most memorable one, I was staring down a giant anaconda face to face. Its scales were very realistic, but with some DMT patterning. It was enormous, but I wasn't afraid. It didn't seem ill-intentioned.
I've also read several reports here where people have talked about having visions of snakes that consume them, and then they end up elsewhere - renewed. This to me lines up with the death-rebirth symbolism.
"Science without religion is lame. Religion without science is blind" - Albert Einstein
"The Mighty One appears, the horizon shines. Atum appears on the smell of his censing, the Sunshine- god has risen in the sky, the Mansion of the pyramidion is in joy and all its inmates are assembled, a voice calls out within the shrine, shouting reverberates around the Netherworld." - Egyptian Book of the Dead
"Man fears time, but time fears the Pyramids" - 9th century Arab proverb