Ssserpent

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

Not much is known about his background except that he is half man, half cobra. He has snake venom like a normal snake does. He appears to be very slimy and have snake-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. He is similar to a Naga.

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
He reappeared again in the Ben 10: Ultimate Alien episode Video Games as the secondary villain. Ssserpent says that he escaped from the Null Void Prison and he tries to fight Ben Tennyson 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 snack." This may mean(since Ben was Four Arms) Ssserpent may be able to unhinge his jaws like a real snake.

Abilities
He is able to strangle his opponents body like an Anaconda, and also bite others which might contain poison and he can spit a acidic liquid described as snake venom by Kevin when Ssserpent spitted 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

Trivia

 * Ssserpent so far is only defeated by two of Ben's original alien forms; Cannonbolt in Vengeance of Vilgax: Part 1 and Four Arms in Video Games.
 * It is confirmed by Dwayne McDuffie that his name is 'Ssserpent' (with three S's, not one).
 * Dwayne McDuffie also mentioned Ssserpent species is possibility the same species mentioned in Ken 10, called Snakepitt.