Chimerian Hammer

The Chimerian Hammer is Vilgax's space ship during the OS, the first one was destroyed when Vilgax was strapped to a warhead by Max Tennyson. Vilgax stayed on the second ship while he was healing. It was destroyed when Max gave the self-destruct sequence to the ship. In the Ben 10: Alien Force episode, The Secret of Chromastone, it appears in a flashback.

Backstory
It is seen in the very first episode of the original series, going after Xylene's ship as it was carrying the Omnitrix. Both ships are damaged in the battle, with Xylenes' ship being completely destroyed (save for the bridge which crash-landed on Earth) and a devastating strike hitting the Chimerian Hammers' bridge, crippling the Murrayan captain in the process as they crossed through the Sol System above Earth. This prompted Xylene to send the Omnitrix in an escape pod set on course for the planet in hopes of reaching Max Tennyson. During the first season of Ben 10, the Chimerian Hammer stayed in orbit above Earth while Vilgax slowly recouperated from his otherwise near-fatal injuries, sending his Hover Drones down to Earth every now and again in order to search for the Omnitrix. After being augmented with cybernetic/biological enhancements, Vilgax decided to go and claim his prize for himself. Landing his vessel near the grasslands of South Dakota, Vilgax and his entire army of drones set out to attack Keystone in order to draw out the wielder of the Omnitrix so he could capture him. After a brief fight against Ben Tennyson, Vilgax managed to capture him and bring him aboard the Chimerian Hammer in order to cut off Bens' hand and gat the Omnitrix, planning to destroy the Earth once they've reached space, only for Max Tennyson to arrive in the Rust Bucket to save his grandson. After overloading the engine core, the Chimerian Hammer was destroyed in a massive explosion, seeming to kill the Chimera Sui Generis and ending his threat to the Earth for good.

It was revealed in the following episode that the Chimerian Hammer was not Vilgaxs' first ship, having already possessed a similarly-designed vessel beforehand when he was younger. He was stealing nuclear warheads from a military base for his own purposes only for the Plumbers to step in and stop him; fastening him to one of the nuclear warheads and firing it at his flagship, destroying it. this incident had Max along with the majority of Earths' Plumbers forces believed that the Chimera Sui Generis died in the explosion.

In season 3 of Ben 10 Alien Force, Vilgax returns with yet another Chimerian Hammer, only its not referred by name. The Chimerian Hammer Mk. 3 is completely different from its two predecessors, it is more sterile and metallic-looking than the otherwise biologically-oriented Mk. 1 and 2 both were. Vilgax, having absorbed the powers of 10 heroes; seemingly no longer needs the Chimerian Hammer in order to traverse space, having the ability to fly and survive in the vaccum for prolonged periods of time, he must require it in order to transport his Energy Transfer Device, along with his Drone soldiers and later his Bioids. Vilgax used the Mk. 3 on several occasions throughout the season (although not as much as the Mk. 2 was), having been used by Vilgax in order to reach Primus (most likely was going to use its weapons systems to destroy the planet just as he planned to do to Earth 5 years ago), and then later appearing in the Final Battle, where he used it to transport his Bioid Army, and after claiming the Omnitrix, was going to use them to conquer even more worlds after destroying the Earth out of his anger for being defeated by it continuously. When Ben activated the Omnitrix self-destruct, Vilgax was left without his shape-shifting army, and damaged the Chimerian Hammer Mk. 3s guidance system in order to crash into Bellwood; destroying it and everything else for 100-miles around: killing thousands as a result. While Ben and Kevin fought against Vilgax, Gwen and Max made it to the control room in order to steer the ship into the Pacific Ocean and ditch it where it wouldn't harm anyone. As the flagship crashed into the ocean, it automatically began to pressurize as the denseness of the ocean began to slowly crush the Mk. 3, where it eventually blew up as Ben Tennyson escaped its destruction as Jetray, leaving Vilgax believed to be dead like the last few times.

In the Vengeance of Vilgax, it is revealed that the Chimerian Hammer Mk. 3 is actually a part of a classification of battleship due to the appearance of multiple similar-looking vessels hovering over the Earth that were part of Vilgaxs' fleet.