Later aliens gave him more specialized powersets, allowing him to react to situations with more finesse than if he was restricted to the original ten. This often forced Ben to get vastly more creative with certain aliens than he should have needed to. Ben's first set of aliens are balanced and strong in their own way, but it left him with few counters or specialists beyond 'this one is strong' or 'this one is smart'. Though others can be unlocked later, it will default to another set of ten if left inactive for too long, requiring older forms to be re-unlocked.

The Omnitrix, due to housing far more potential alien forms than any one user could hope to sort through, generally operates in sets of ten randomly selected (though generally balanced) forms.

Since Ben can only use one transformation at a time, his set of powers will change according to which form he is using.

Though by the last season of Alien Force this is no longer true, as Ben knows exactly how to remove the thing whenever he wants. This prevents villains from simply taking it from him.

Clingy MacGuffin: The thing is stuck on Ben's wrist.

Most commonly in the center of the chest, but it does vary for some.

Chest Insignia: The Omnitrix's symbol will appear somewhere on the body of every alien it transforms its wearer into.

This frequently causes him to take the wrong transformation, turn back to normal at the wrong time, or merely make mistakes.

Black Box: Ben has no idea how the Omnitrix works at the beginning of the story the best he can do is turning and pushing the dial.

Female Tetramands are stronger than males, and Ben as Fourarms faced off against the Warrior Princess Looma, Warlord Gar's Greatest Warrior and not only matched her in strength, but defeated her in combat.

Downplayed but noticeable with Fourarms as well.

The only other Incursean to look significantly different is Attea.

Most blatant seen with Bullfrag, a genetically optimal and healthy Incursean: While the standard Inkursean grunts are human-sized, gaunt, and frail-looking due to their rather poor diets (except for Milleous), Bullfrag meanwhile is taller than the average human and has a Heroic Build.

Basically, they're to their species as Captain America is to humanity (peak and perfect physical condition). All of the alien forms present in the Omnitrix are actually the optimal genetic specimen of their species.

The device created by Azmuth that Ben Tennyson uses to transform into different aliens.

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