Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
Eve Batiste is a 10-year-old girl who lives in a mansion on a bayou in Louisiana in 1962. She is the descendant of a slave named Eve, a sorceress who used her medicine to heal a wounded French general. He freed her and married her and built the mansion. Eve's psychic and voodoo powers have been passed on to the young Eve and her aunt Mozelle. A snake shows up in three separate scenes.
After Eve's mother has her fortune told by a psychic who implies that her three children are in danger, she rushes home to keep the children inside the house to protect them. Before she gets home, Eve and her brother are sitting on the shore of the bayou and Eve is poking a motionless snake with a stick. She conclude that the snake is dead, and picks it up. After it moves and she discovers that it's alive, she throws it down and runs home screaming. The snake scene seems to be added to create more tension regarding the impending danger for the children, but whenever there's a snake and someone named Eve, we can't help but think about the snake representing evil. A while later, Eve is going crazy from being locked in the house, so she sneaks into the room of her aunt Mozelle, a voodoo practitioner and "psychic counselor" where she opens a box and finds a stuffed rattlesnake that must is part of Mozelle's witchcraft arsenal. We don't see her brother when he wakes up next to the snake, but we hear him screaming and screaming as Eve smiles.
Eve becomes upset with her father's infidelity to her mother and his brutality to her sister so she decides to kill him with voodoo. She goes to the same witch her mother visited, bringing some of her father's hair, and asks her to use her voodoo to kill him. Eve returns to the witch in a few days when the witch tells her that she made a wax coffin and put the hairs in the mouth of a snake and buried it in the Batiste family graveyard. As she tells Eve that, we see a shot of the same snake in the same place that we saw earlier before Eve picked it up. This snake is probably supposed a flashback in Eve's mind as she pictures the snake she saw recently. I'd rather believe that than think that they simply used the snake snake to avoid having to film another one.
The stuffed rattlesnake is a juvenile Western Diamond-backed Rattlesnake. I'm not sure about the live black snake since it's hard to see. It would be a water snake in the real setting, but they're ornery, so I'd guess that they used a black rat snake or a small indigo snake, maybe one whose temperature was chilled so it would not be able to move quickly.