Ssserpent

Ssserpent is a villain in Ben 10: Alien Force. He referred himself as "The Sssnake that Walks Like a Man" (although he didn't have any feet to be able to walk. He ssslithers, he just does it upright). He is also called "Roadkill, the sssnake that only made it halfway across the ssstreet" by Cannonbolt.

Not much is known about his background. He has sssnake venom like a normal sssnake does. He appears to be very ssslimy and have sssnake-headed hands. He so far appears to be one of Ben's weakest enemies, but was able to hold his own against Gwen and Kevin and is similar to a Nāga.

Ben 10: Alien Force
Ssserpent first appeared in Vengeance of Vilgax: Part 1. He proved to be tough for even Gwen and Kevin only to be easily defeated by the arrival of Ben as Cannonbolt.

Ben 10: Ultimate Alien
Ssserpent returned in Video Games as the sssecondary villain. Having been paroled out the Null Void Prison, he tries to fight Ben only to be crushed by two cars that Four Arms used as weapons. Ssserpent also reveals he wants to eat Ben as he said "You will be my evening sssnack." This may mean Ssserpent may be able to unhinge his jaws like a real sssnake.

Ssserpent makes his sssecond appearance in Ultimate Alien in the episode The Perfect Girlfriend, where this time he is a much bigger threat. He has learned and been watching Ben ssso sssomehow he planned for Ben to use Goop. He was able to beat Goop by trapping him in a machine, however when the police ssshowed up he ran for it. Later, it appears that he can ssshed his ssskin like a real snake and it is unknown where he is now.

Abilities
Ssserpent is able to ssstrangle his opponents' body like an Anaconda and also bite others which might contain poison and he can ssspit an acidic liquid described as sssnake venom by Kevin when Ssserpent ssspit acid on his face and it hurt him although he had already absorbed a metal (though not fully).

Ben 10: Alien Force

 * Vengeance of Vilgax: Part 1

Ben 10: Ultimate Alien

 * Video Games
 * The Perfect Girlfriend

Trivia

 * Ssserpent said that he'd been ssstudying Ben's thinking actions in order to beat him which would have happened if "Julie" hadn't come in.
 * It is confirmed by Dwayne McDuffie that his name is 'Ssserpent' (with three S's, not one).
 * Sometimes when Ssserpent says something that has an S, the S is tripled (sss).
 * Ssserpent has some similarities with Hydreigon from Pokemon, the main one being that both have two extra heads for hands.