The Story:
When 10 year old Ben Tennyson discovers a mysterious device, he gains the power to change into 10 different alien heroes, each with unique awesome powers. With such abilities at his disposal, Ben realizes a greater responsibility to help others and stop evil doers, but that doesn’t mean he’s above a little super powered mischief now and then.

wat alien do u want to be?
1. wild mutt - more animal than a humanoid alien, wild mutt has no sight but has heightened sense of smell, taste and hearing. This alien is fast and agile and can fire squills from his back.
2. fourarms - standing 12 feet tall, this formidable four-armed alien can use his tremendous strenght to dish out the punishment, while his armored skin protects him from harm.
3. grey matter - standing 5 feet tall, grey matter is believed to be of the smartest alien races in the galaxy, giving you temporary boost in intelligence! suggesting to shot and destroyer ^^, no offense
4. XL8R - a dinosaur-like alien with a lightning-quick reflexes and the ability to reach speeds in excess of 300mph. He can also manipulate friction which enable it to run walls and non-solid grounds.
5. upgrade - a biomechanical alien that can merged with a device and "upgrade" it into an incredible piece of Ultra-tech far more advanced than any existing Earth technology
6. diamond head - a crystalline alien that can reflect light and beam-based weapons. It's body is harder than diamond making it invulnerable to most physical attacks and allowing it to cut through almost everything
7. rip jaws - an aquatic alien that can breathe underwater. He can change his leg into a large tail with fin and is remarkably fast and agile in water. His weapons are his claws and his powerful jaws
8. stink fly - a wing insectoid alien and expert flyer, he uses his pincers and sharp tails as impressive natural weapon
9. ghostfreak - a shadowy alien with ghost-like powers, able to phase through walls and turn invisible putting fear into the hearts of criminals everywhere.
10. heatblast - comes from an alien race that lives on the sun. He can projects bolts of fire from his hands and mouth and create fireballs. He can also absorb flames and heat thus can easily put out fire as quickly as he can start one

truth!! omnitrix don't have only 10 aliens.. it has approximately thousands of them...
11. cannonbolt - while trying to unlock the secret of the omnitrix, Ben transforms into a large, fat alien.. it can curls up within the thick armor on his back and becomes an unstoppable wrecking ball!
12. wildvine - while trying to escape from being entangled by enemy mushroom, Ben transform into a living plant with a vine whip and a plant bomb. Like a plant, it is much more powerful at morning,
13. way big - Ben travel through space to meet the creator of the omnitrix and stop it from it's destructive countdown. while fighting Vilgax, ben managed to stop the destructive countdown and was gift by the creator "way big". The biggest alien ever, standing 100 feet, he can take out an entire army!
14. upchuck - a small alien with 4 stretching tongues with can swallow anything and then fires a toxic ball..
15. eyeguy - half bat, half reptile with eyes all over his body .... it can fire a powerful beam at it's largest eye in his stomach
16. ditto - an alien which has the power of duplicating.... but if one is hurt.. all of them hurts also....
truth! if an alien touches the omnitrix, it's DNA will automatically copied and the user can transform into that alien
17. mummy alien - while trying to stop the mummy alien from collecting magical stones, the mummy touches the omnitrix and ben got it's DNA... since Ben can't control the omnitrix yet and tries to fight fire with fire, Ben ends up "upgrade" and defeated the mummy
18. electricity freak - teaming up with the mummy alien, this two tries to revive the slain ghost freak, while ghost freak was revived, ben got electricity freak DNA and ends up defeating ghost freak with this new alien
19. iguana frost alien - ben didn't have this till the future, when he meets Ben10k, with over 10thousands alien.. ben10k unlocks the secret of the omnitrix and by using this alien, he defeated Vilgax