The Once and Future Ben is a Ben 10 comic story published in the Cartoon Network Action Pack series (based on the original series), published by DC and Cartoon Network. This comic appears in issue 23 of the series.
While discussing with Gwen whether the two are immortal, having seen their future selves, Ben is shot at by a taser by Melville, only to have it be reversed back by a time travelling Ben 10,000.
Ben 10,000 alerts the two to Vilgax 3000 - a revenge seeking, time travelling descendant of Vilgax from the year 3000, who's planning on changing history by killing Ben 10,000's past self, after getting defeated by him in his adult form.
Ben's shocked to find out that history can be changed so that he'll be killed, while Ben 10,000 muses that Vilgax 3000 had to use the Omnitrix as a beacon, explaining why he couldn't go to before Ben wielded it - also commenting that it is a brilliant plan.
Ben lets his future self 'adjust' the Omnitrix -thinking it to be to unlock some new aliens- however he reveals himself to be Vilgax 3000 himself, and having deactivated the Omnitrix, morphs his tentacle hands into a weapon to kill Ben once and for all.
Before he can though, the real Ben 10,000 - and Future Gwen too appear. Ben is given Arctiguana, and both selves shoot him through Future Gwen's portal back to the Ice Age - 20,000 years ago- to freeze.
Before the pair go back to the future, they wipe the minds of everyone involved to preserve their timeline. Ben and Gwen go back to arguing while Melville has presumably forgotten his entire identity, down to his name.
By Ben 10,000
- The phrase "I would have [/would'a] gotten away with it too, if it wasn't for you meddling [/Pesky] kids" is cut off. A reference to the iconic line from Scooby Doo (originally from Hanna-Barbera, which became Cartoon Network).
- We can see the sign Jellystone Park, either a reference to 'Yellowstone Park', which did in fact appear in the episode The Big Tick - or a direct reference to the chain of 'Yogi Bear'-themed parks of the same name (based off of the show, also by Hanna-Barbera).
- The Vancouver Island Marmots are referenced to be endangered, as they are in the real world, with the numbers given being somewhat accurate too.
- Time travel works differently in this story to how it was shown in the episode Ben 10,000, and the story's rule of having to wipe their past selves' memories is explicitly shown to have not happened after the first episode.
- Grammatically, the second speech bubble should have the word 'gotten', not 'got'. Though this could just be how the character would speak, so isn't much of an error.
- Though unexplored, there is no reason why Ben and Gwen would be comfortable with Melville knowing Ben's secret identity, as Ben de-transforms right in front of him.
- The portals seen created both by the time machine, as well as Future Gwen look completely different to the ones seen in Ben 10,000.