De acordo com o Ben 10 Wikia , o Anihilaarg (presumivelmente uma contração das palavras "aniquilar" e "aargh") é uma arma do juízo final real que é vista em um episódio e referenciada em outro .
Na página da wikia;
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.