Pierce Wheels

Pierce Wheels is a rogue Plumber's kid that appears in Ben 10: Alien Force. It seems that Pierce is a half porcupine alien/half human, his exact species unknown, as is much of his past. He works with a Tetramand named Manny and a Kineceleran who is also his little sister, Helen, in Plumbers' Helpers, trapping what they thought were dangerous aliens out to conquer Earth. Unlike Manny and Helen, after sending a kid with a Plumber's Badge to the null void he began to have doubts about what they were doing. However, before he could voice his concerns, he was believed to have been killed when an attempt to destroy a DNAlien went wrong, but this was actually revealed to be false when the weapon they were using is shown to be a vortex to the Null Void. He is the mirror image of Ben on the team, as Helen is to Gwen and Manny is to Kevin.

Ben 10: Alien Force
Pierce was stuck in the Null Void and began working with Max Tennyson to protect its inhabitants from D'Void, gathering other Plumbers who were trapped/lived there. He also appeared in War of the Worlds helping against the alien threat/onslaught and when the battle was over he became a pupil of Grandpa Max. He is also like the mirror of Ben Tennyson and often share the same views.

In Above and Beyond, Pierce acts as the Plumbers' Helpers leader on a mission to save Magister Max Tennyson from a rampaging Ben aboard a Plumbers' Space station. Pierce is attacked by Goop. He is very respectful of Grandpa Max usually referring to him by his Null Void codename "The Wrench" or by his Plumber rank of "Magister". He is shown to be a capable leader who believes in working as a team. He often clashes with Manny over his leader position, mainly due to Manny's brash personality. He and his team manage to overcome their differences and work as a team to defeat Ben. When they discover the space station they are on is going to crash into the city of London, Pierce and the others realize the only way to stop it is to blow up the station. With their shuttle gone Pierce and the others show they are willing to sacrifice themselves for the greater good. However Max appears along with Ben and reveals the space station is a Plumbers' Training facility and Ben's rampage was a test. They are then told that because of their defeating Ben (as well as their heroic actions in trying to prevent the space station from hitting London) they are approved for training at the Plumbers' Academy.

Ben 10: Ultimate Alien
In The Purge, Pierce was shown wearing an ID Mask when on a date with a girl which is crashed by The Forever Knights who want him to leave the planet. He was killed by them when he explained that he was unwilling.

Powers and abilities
Pierce has the ability to grow quills from his body, similar to Argit and Porcupine. He can grow and retract them at will, as well as being able to shoot them as projectiles or break them off in order to use them as weapons. He is also highly skilled in acrobatics and hand-to-hand combat, regularly using them in combination with his powers.

Ben 10: Alien Force

 * Plumbers' Helpers (first appearance)
 * Voided
 * War of the Worlds: Part 1
 * War of the Worlds: Part 2
 * Vengeance of Vilgax: Part 1
 * Above and Beyond

Ben 10: Ultimate Alien

 * The Purge (killed by The Forever Knights)

Trivia

 * Helen Wheels is Pierce's adopted sister (as revealed by Dwayne McDuffie) though it is unknown what happened to their parents.
 * Pierce claims he has to babysit Manny and Helen every day because of their aggressive arguments, as well as having a few himself with Manny over leadership and ego issues. This resembles Ben's dialogue in Plumbers' Helpers when he tells that "What am I, your babysitter?".
 * He resembles Spyke from X-Men: Evolution who can also shoot quills from his body, as well being able to break them off and grow/retract them at will. His strength and speed are about average though despite this Grandpa Max is shocked when he discovers Pierce defeated Ben, even when Ben was in human form, and is told Ben "let" him win. He himself admits he is not a good fighter.
 * It is confirmed by Dwayne McDuffie that the DNA of Pierce's alien race is in the Ultimatrix.
 * Pierce is the only plumbers kid to not have been from an already known alien species.
 * Matt Wayne confirmed that Pierce was killed in The Purge.