Annihilargh

The Anihilaarg was an extremely powerful and dangerous weapon used by the ancient Contemelia. It looks like a purple box with a red button inside it. The Anihilaarg had the power to destroy an entire universe when activated.

Backstory
The Anihilaarg was used by the Contemelia as they traveled across the multiverse playing various practical jokes on the inhabitants of a universe. If the Contemelia did not like a particular dimension, they would use the Anihilaarg to reduce it all to nothingness.

At some point in time, the Contemelia died off, but their vessel still flew across the multiverse labyrinth, as it passed into legends along with its weapon of judgement.

Ben 10: Omniverse
The Anihilaarg first appeared in So Long, And Thanks For All The Smoothies, where the vessel materialized in the universe and appeared above the Earth, Argit was sent aboard the ship by Milleous to obtain the Anihilaarg while the Vreedles sought it for themselves.

Later in the episode, it was accidentally activated when Ben, Rook, the Incurseans and the Vreedle Brothers were fighting to obtain it. It destroyed the entire universe, but Ben recreated it as Alien X. With the Anihilaarg activated, it's purpose of destroying a universe was complete and was rendered useless as a weapon.

Everyone present believed that the Anihilaarg was defective, unknowing that the universe was even destroyed in the first place as Rhomboid went over and crushed the Anihilaarg underfoot, destroying it completely.

In Mud is Thicker than Water, it's revealed that Blukic and Driba fixed the Anihilaarg and that it's being kept at Plumber Headquaters with a fake being used as bait.

Appearances

 * So Long, And Thanks For All The Smoothies (first appearance)
 * Mud is Thicker than Water (fake)

Trivia

 * According to Derrick J. Wyatt, the Anihilaarg will make another appearance at some point in Omniverse.
 * According to Ben in Mud is Thicker than Water, the Anihilaarg is the most dangerous weapon in the universe.
 * Its name is based on Annihilate.
 * All throughout So Long, And Thanks For All The Smoothies, Ben had a hard time of pronouncing its name, causing everyone else to say it for him. He finally said it right as Alien X.
 * It is said that the Anihilaarg isn't its full name, saying that "Anihilaarg" is all that could be said of its full name before it is activated.
 * This is a reference to "The Castle of Aaargh" from Monty Python and the Holy Grail, as it was believed that it was all that was written by the original writer before he died.
 * The Anihilaarg is similar to Mavel Comics' Ultimate Nullifier, owned by Galactus, the Devourer of Worlds. It too has the power to destroy an entire universe.