Diamondhead

Diamondhead is a Petrosapien alien from the planet Petropia. He was first used in the first episode, And Then There Were 10.

Powers and Abilities
Diamondhead's body is composed of an extremely dense and durable organic crystal, making him nearly invulnerable. He can manipulate the atomic structure of his diamond physiology at will, allowing him to create crude crystal weapons from any part his body on demand or fire crystal shards from his hands. In certain ways, he can reshape his projectiles into certain shapes. He can even control those that are not connected to his body. This same ability also allows him to regenerate to an extent, such as regrowing lost limbs.

In addition to growing crystal from himself, Diamondhead can grow crystal over other objects. In the episode, Vengeance of Vilgax: Part 2, Ben as Diamondhead, seems to levitate three pillars of crystal that he controls to aim toward Vilgax, defeating him. Lasers and other similar weapons are useless against Diamondhead, as his crystal body acts as a prism, refracting the beams. He also has proved strong enough to easily beat Kevin, defeat Vilgax, and smash apart various objects with relative ease (an example of this is when he mutilated a semi truck just by sneezing). The one drawback to Diamondhead's crystal form is the crystal itself, which can shatter if exposed to sufficiently strong sonic vibrations. Though his diamond structure is durable, it can be damaged with sufficient force. While Petrosapiens can regenerate limbs, there is a limit to how much damage they can recover from. He also seems to be able to survive if shattered, given his head is still intact.

Weakness
Diamondhead weakness is super sonic.In Ultimate Sacrifire he is hurt by sentient Ultimate Echo Echo super sonic.

Gwen 10
After turning into Heatblast, she then turns into Diamondhead after learning about many of the other aliens, but she doesn't turn into Wildmutt after Heatblast like Ben had done in And Then There Were 10. Her fight with the giant Vilgax drone almost mirrors Ben's fight in the pilot. However, she uses her book smarts to effectively rebound the laser blast without doing more than necessary damage.

Race Against Time
Diamondhead appears as the third alien Ben transforms into in a live-action movie and fights Eon once but gets away. Ben spent his remaining time as Diamondhead in the girls' locker room.

Alien Force
Diamondhead makes an appearance in the third season premiere of Alien Force, regenerating from Chromastone's remains after Vilgax destroyed him. Diamondhead's appearance is slightly altered (but similar to his appearance in Ben 10,000), with a primarily dark blue uniform that also covers part of his head (however, all petrosapiens have this natural "costume". It wasn't seen before since Ben's clothing covered it), and his crystal body is more blueish and dosent make the same crystal-like noise when he walks anymore. But it is just possible that Diamondhead's dark purple uniform never appeared before because both Diamondhead and the Petrosapien race were restored by Sugilite's DNA. It is also a fact that Diamondhead has six crystals in his back (instead of two) and more two in his chest, exactly like Sugilite. In this series, his crystals can explode, and he demonstrates the ability to psychokinetically control the crystal he creates.

Diamondhead's body is different in that his Omnitrix symbol is now in his chest and his eyes are now green. He also has a similar body structure to the one of Chromastone, a related species. In the episode The Secret of Chromastone, all Petrosapiens have a dark purple body (in the original series, we never saw that, since Ben, Tetrax, and all the Petrosapiens were wearing clothes). Ben transforms into Diamondhead after Vilgax destroys Chromastone's body, but the crystals that made up Chromastone re-constituded into Diamondhead, giving Ben access to this form once again. As Diamondhead, Ben states "You're in trouble Vilgax; I've had a lot of practice with this one," indicating Diamondhead is one of the alien forms that he had a lot of experience with (this may be in reference to a scene from an episode of the original series, in which a young Ben can be seen training in this form under the guidance of Grandpa Max), possibly due to it being one of his original ten alien forms. Ben proves this by using it to literally crush Vilgax, forcing the villain to yield defeat. Ben's use of Diamondhead to defeat Vilgax is ironic since he is the one ultimately responsible for the destruction of Petropia.

Diamondhead is now once again selectable in the Omnitrix. Ben briefly transforms into Diamondhead in the episode Single-Handed, after becoming trapped in the Null Void after he is dimensionally displaced from his left hand (the hand that wears the Omnitrix) by the bounty hunter Sunder. This saves Ben's girlfriend, Julie Yamamoto, from Sunder, while she is trying to protect Ben's left hand and the Omnitrix. Ben's dimensionally displaced hand protects Julie by firing Diamondhead's crystal shards. However, this causes problems for Diamondhead, as his left arm, even with the hand gone, also fires shards, unintentionally destroying a rock bridge he was walking on. Diamondhead also appeared in the episode In Charms Way, fighting a hypnotized Kevin. Diamondhead also appears in The Secret of Chromastone by releasing Sugilite inside him, where he saves his home planet Petropia, with the crystal Vilgax had, that can regenerate Petropia and their species. He was also used by Albedo to fight and kidnap Kevin and one of the alien forms Vilgax's army of bioids take.

His appearance in Alien Force demontrates that Petrosapiens and Crystalsapiens are somewhat related.

Jimmy 10
He is mentioned in the series, and may be unlocked on the Decatrix.

Rent 10
Diamondhead first use in Meet the ten part 2 to defeat the giant drone.

Len 10
Len's version of Diamondhead is Diamondbread. He is made of hard, frozen bread, and has the same powers of Diamondhead, except he shoots frozen bread instead of diamonds.

Zac 10 Master of the Ultimatrix
The Rise

Ben 10: Generations

 * He makes his first reappearence in "This Day Just Get's Worse" to fool Vulkanus into having his Machine destroyed