Snakes!!!! Are!!!! So cool!!!!!!!!!!!
I know a lot of people don't like snakes. They think they're scaly and slimy and mean. But MAN are they cool. And they are packed with magical and religious significance.
If you're in an area like mine, one of the first stories you remember involving a snake was the Garden of Eden, where a snake convinced Eve to eat the forbidden fruit. In this context, the snake can be seen as a trickster, but also as a sort of teacher (the forbidden fruit of knowledge, y'all).
In the Epic of Gilgamesh, a snake steals the herb that grants immortality. So this snake, like the one in the Garden of Eden story, has prevented mankind from having eternal life on Earth. But... can it be seen as a blessing in disguise? Losing the herb forces Gilgamesh to face reality and learn to live his life in the moment. Again, the snake is a teacher.
I don't know much about Vodou, admittedly, but I do know that one of the major figures in that religion is Damballah, a serpent that either created the world or was one of the first things created. In this religion, the snake is closely linked to creation, as in the Garden of Eden story.
The ancient Egyptian god Atem is a creator god that was thought to take on the form of a snake which would renew itself every day. Another snake associated with creation. And, maybe this is just me, but I find it interesting how close the names "Atem" and "Adam" are.
Another Egyptian god, Apep, is the god of chaos. He takes the form of a snake and opposes order (Ma'at). This seems to align with the snake from Eden, which encouraged Adam and Eve to break the rules.
Moving away from gods...
Snakes are just magical all around. They shed their skins, making them a symbol of renewal and change. They slither down into the ground, up into trees, across the water - they can go anywhere, almost every physical plane of existence. They're cold-blooded, giving them an other-worldly property. They can unhinge their jaws to swallow things many times their size. Some are venomous, which can kill a person, but the venom can sometimes be used to create cures. Maybe this is why snakes are also a common medical symbol, as in the Caduceus.
In conclusion, snakes are fucking rad.