Seviper is a purplish Pokémon with golden "plates" on its body. Both of its fangs are red but one side of its face is light purple while the other side is a darker purplish color. Its eyes are also red and the also have gold "plates" on them.
Seviper is aggressive and has a nasty disposition and has no qualms about stealing other Pokémon's food. It is known to wrap its body around its victims so that they cannot move. Like most Pokémon, Seviper is quite clever and it is observant enough to notice where a trap might be. It can also be quite affectionate with its trainer.
Seviper first appeared in A Tail with a Twist. A Seviper is attacking other Pokémon to steal its food. Soon when the gang has lunch, May's Torchic is attacked by a wild Seviper and also gets its food taken. Ash's Treecko sees it attacking Torchic and tries to help. After Treecko attacked it a few times, the Seviper runs away. Later in the episode Jessie, James and Meowth are having lunch. Once they ran out of food, Jessie gets a secret rice roll she was hiding from James and Meowth and while they where fighting over it, the Seviper steals, and eats it. Jessie gets mad and, when the Seviper bites her hair, Jessie became very angry and attacked it. She almost killed it, but James and Meowth told her to catch it, so she did.