Ken 10 is the forty-sixth episode of Ben 10.
In the future, Four Arms is fighting Vulkanus and transforms back into Ben 10,000 and places Vulkanus in a Null Void egg. Ben 10,000 then transforms into XLR8 and runs off to his headquarters. When he arrives, his son, Kenny, is celebrating his 10th birthday. Ben 10,000 gives Max Vulkanus' Null Void egg to place into the Null Void. Kenny explains to his party guests about what Ben does. Gwendolyn arrives in a hologram and gives Kenny a rock creature as a pet. Kenny blows out the candles on his cake and opens presents. Max gets him a hoverboard and he gets several other toys. Finally, Ben comes and gives Kenny his gift: which is an Omnitrix that comes pre-loaded with 10 aliens and a limiter, which Kenny doesn't like. An alarm rings and both Tennysons transform into XLR8. The XLR8s run off and fight Sploot. XLR8 (Ben, 10000) transforms into Cannonbolt while XLR8 (Ken) gets stuck in slime. Cannonbolt transforms into Heatblast, and then transforms back into Ben 10,000 before getting Sploot with a Null Void egg. Diamondhead fights Mot Snikrep as a boy watches on a screen. Diamondhead transforms into Spitter and Ken as Buzzshock attacks as well. Buzzshock is about to defeat Mot Snikrep, but Articguana freezes him before Buzzshock can win. At HQ, Ben 10,000 gives Max Snikrep's Null Void egg. Kenny is upset because Ben didn't let him do anything. Ben says that Ken's job is to watch and learn. Kenny storms off on his hoverboard. He rides with another boy, Devlin, and they compete to do tricks. Kenny transforms into Wildvine to win. Afterwards, the boys become friends. That night, an alarm goes off because someone is attacking HQ. The door blows up and it is Kevin.
Ben sends Kenny away, believing Kevin too dangerous to fight. Ben transforms into Four Arms, who walks off to fight. Four Arms and Kevin fight and Four Arms transforms into Cannonbolt. Kenny, in his room, notices a vent. Cannonbolt transforms into XLR8 in the Null Void chamber. XLR8 tells Kevin that he moved to projector and readies an egg. Grey Matter comes out of the vent, but he reverts back into Kenny. XLR8 is surprised to see him. Kevin leaves and Snare-oh gets Kenny out of the vent. Kenny gets angry at Ben and storms off. The next day, Kenny and Devlin speak about their dads. Devlin suggests that he and Kenny find the Null Void projector and they fly off. They go to the Rust Bucket after Max gets out and walks away. They sneak in and look for the Projector, which Kenny believes is in the Rust Bucket. Kenny transforms into Ditto and creates clone to look for the Projector. Outside, Gwen tells Ben that he needs to give Kenny a chance to earn his trust. One of the Dittoes finds the room with the Projector and he, Devlin, and Kenny's pet go in. Devlin mutates into Kevin's original mutant form and releases his father just in time for Ben to arrive. Kevin runs up to and grabs Ditto, who reverts back into Ken, and he reveals that being imprisoned in the Null Void was the best thing that ever happened to him as he has now absorbed that powers of 11 000 aliens and transforms into an even more monstrous form than before. Kevin mercilessly attacks Ben, Ken and even his own son Devlin. While Ben takes the fight outside Ken has an idea to defeat Kevin.
Ben transforms into Four Arms and he still fights Kevin, but as before Kevin weakens Four Arms, who transforms back into Ben. Ken transforms into Grey Matter to enter and later transforms into Spitter and then transforms into Buzzshock. After Grey Matter transforms back into normal, Ken reveals he used Grey Matter's brain to remove the Omnitrix's limiter so he can transform into alien forms at will. Kevin grabs Ken and is about to throw him, but Devlin comes in to defend him. Devlin explains why he freed Kevin - he wished his father would have cared about seeing his son again but instead finds that he doesn't care at all as he is only willing to kill the Tennysons. Devlin cries upon this realization but then resumes fighting against his father. Ken transforms into XLR8. Devlin and XLR8 are thrown away and XLR8 transforms back into Ken who passes out.
Ben wakes up and sees what happened to Ken, angering him. Ben transforms into Way Big and mercilessly crush Kevin, who transforms back into normal and Way Big transforms back into Ben, but he gets back up. Kevin is about to attack Ben and Ken again, but Devlin imprisons Kevin in a Null Void Grenade. Max states that he has a 'special place' reserved for Kevin so he can't absorb any more alien DNA. Ken asks Ben if he can use all ten thousand of his heroes, but Ben says not to push his luck.
Devlin is about to leave until Max grabs him. Ken says he should stay with them, so Devlin becomes part of the Tennyson family. Later, Ken's rock pet regenerates and is alive again making him happy.
- Ken receives his own Omnitrix.
- Ken meets Devlin.
- Kevin escapes from the Null Void.
- Devlin moves in with the Tennysons.
- Ken Tennyson (first appearance)
- Ben 10,000
- Gwendolyn Tennyson
- Max Tennyson
- Gwendolyn Tennyson (Ken's sister; first appearance)
- Devlin Levin (first appearance)
- Ken's Pet (first appearance)
- Billy (first appearance)
- Unnamed Alien Kid
By Ben 10,000
- Four Arms (x4)
- XLR8 (x4)
- Cannonbolt (x2)
- Diamondhead (x2)
- Way Big
Naming and Translations
|Hungarian||Ken 10||Ken 10|
|Portuguese (Br)||Ken 10||Ken 10|
|Spanish (HA)||Ken 10||Ken 10|
|Spanish (Spain)||Ken Ten||Ken Ten|
- One of Ken's friends who attends his birthday party bears a close resemblance to Billy from The Grim Adventures of Billy & Mandy. He also shares Billy's voice actor, Richard Horvitz.
- This episode celebrates the three year anniversary of the series.
- It is revealed that adult Gwen can tame rock monsters as pets.