I know of a story for the obvious Ben 10-Transformers: Animated crossover:
The Autobots must form an alliance with the Plumbers to stop the Decepticons from conquering the Omniverse.
I imagine that Ben Tennyson and Sari Sumdac would get along well, since they’re both young “chosen ones” who value connections and bear a lot of responsibilities. Chances are Ben would convince Optimus Prime to accept being a hero.
I can also draw parallels between Vilgax and Megatron as both are remorseless, power-hungry conquerors. Ben would undoubtedly compare the leader of the Decepticons to his greatest, most dangerous and most persistent enemy.
Here are personal headcanons I came up with for the shared universes of Ben 10 and Transformers: Animated:
Despite the attitude of most Cybertronians towards organics and non-mechanical beings in general, Ultra Magnus and some of his predecessors respect those such as the Galvan. Because of this, they helped provide the resources that would be used for creating things such as the Galvanic Mechamorphs. Unfortunately, the Cybertronian Civil Wars led to disagreements and strained relationships between the Cybertronians, Galactic Enforcers and Plumbers.
Cybertronians have largely not heard of Ben, the Enforcers or the Plumbers due to the loss of history records and their species’ isolationism. In turn, Ben and most of the Earth Plumbers have also never learned about the Cybertronian race. However, certain Cybertronians are aware or at least have knowledge of things like Ledgerdomain and the Null Void. In addition, the Contumelia and other higher beings have a spiritual connection to Cybertronian figures such as Primus and Unicron.
My Classic Ben 10 Headcanons And Possible Pseudocanons/Semi-Canons, etc.
Here are some headcanons and possible pseudocanons/semi-canons I came up with for classic Ben 10.
The Omnitrix was still meant for Ben’s grandfather Max. Every genuine Omnitrix across the multiverse is actually self-aware in some way. Whether or not the theories involving his Anodite heritage are correct, Ben must exercise caution due to the strain on his body and mind. The troubles with every Omnitrix knockoff and prototype were caused by limitations, design flaws, program errors and incompatibilities. By the time Ben got the complete version of the Omnitrix, anything that went wrong was due to external tampering and misuse. When an Omnitrix-based device scans suitable life forms it alters the DNA to produce the healthiest, strongest and most natural versions. The Omnitrix’s genetic copies came to life for reasons similar to why the original Ultimatrix’s hyper-evolved forms gained sentience. Ben eventually regained every DNA sample ever lost from or locked out of the Codon Stream.
Azmuth and Ben secretly respect each other but are reluctant to admit it. The First Thinker was initially disturbed by the idea of anyone using his greatest and perhaps most powerful and dangerous creation since Ascalon, but as time passed he slowly warmed up to Ben. Meanwhile, Ben stubbornly believes Azmuth shouldn't view everything solely through logic and intelligence, but he silently acknowledges the Galvan's reach and grasp as exceeding his own in a way.
Kevin’s father Devin was real, albeit having started out as not quite the kind of person Max described him as due to the nature of his powers. Servantis set him up to be killed by Ragnarok for defecting from the Rooters and erased almost all evidence of his existence, only keeping Kevin and Max’s memories intact for his own benefits. Servantis ironically decided to use Kevin since he possessed his father’s abilities and released Ragnarok as a way of providing closure.
Race Against Time is still canon, as Eon is now a Chronian in the body of an alternate Ben. Since the future of Ben Prime's timeline is murky at best, the past and present continue influencing it. The different Bens seen in the reboot special Alien X-Tinction (excluding Reboot Ben and Evil Ben) are representations of Ben Prime. Other non-TV works are canon so long as they do not deviate from the source materials. Any retcons are caused in-universe by misconceptions and inaccuracies. The lore in 5 Years Later (minus almost everything previously retconned) is canon.
Ben initially started off as eager and reckless but mellowed out, becoming quieter and more reserved. Following the vacation and road trip that changed his life, Ben struggled in readjusting to what he once saw as normal. Putting the Omnitrix back on reignited all anxieties, though the rest of his family finding out helped ease the burdens. After being dumped in Ultimate Alien, Ben lost all interest in romance. His obnoxious behavior, especially after becoming famous was just a facade to keep up appearances and cope with his insecurities. Upon being renamed “Ben 10,000”, he devoted his entire life to being a hero until meeting his younger self. From that point forward, he spent more time with his family and friends.
Just a quick derpy thing I felt like writing, because yeah. I don't know if this really qualifies as anything.
Title: Sea Prunes
Genre: Humor/family?? I guess?
In which Tahno will throw a hissy fit over the littlest things.
Just as Ming was cleaning up, Tahno stomped into the room, his pale face contorted in irritation.
"Ming?" He began, his voice tight and venomous.
Ming looked over his shoulder casually. "Yeah?"
The dark-haired leader held up a bowl of noodles, his lip curling in disgust as he pointed to something dark nestled in the stir-fried noodles.
"What. Is. That?"
Ming smiled patiently. "It's a sea prune."
The subsequent noise that escaped Tahno's lips sounded like a bizarre cross between a squeak and the grunt of an adult saber-toothed moose lion about to charge.
"Sea prunes?" He sputtered petulantly. "I hate sea prunes!"
Sometimes Ming wondered how it was he and Shaozu put up with Tahno's diva attitude. Here he was, a grown man, stomping his feet and pouting while waving around a bowl of noodles like a four-year old.
"Make new noodles."
"No."
"Do it."
"You do it."
Tahno growled. "You make them."
Ming folded his arms across his chest. "Why can't you do it?"
"Because you make them better."
"Tahno, it's not that hard. You boil them, you strain them, you add sauce. What part of that puzzle are you having trouble piecing together?"
Tahno gave him a dirty look. "I know the process. They just don't taste as good when I make them."
"So?"
"So make me new ones."
"Just pick the prunes out, you baby."
Tahno gagged. "Ugh, no. It won't make a difference anyway. They've been tainted already. This bowl smells overwhelmingly like prunes." He said as he held the still steaming bowl away from him in disgust, holding his nose closed with two fingers.
Ming slid a hand down his face.
This would, undoubtedly, go on for a while. Tahno was not one for insubordination, whether it was in the ring or outside. But if it wasn't for the fact that the three of them had been friends since childhood, Ming might've cared.
Tahno could be insufferable on his best days, and downright apocalyptic on his worst. So was the way of someone who was used to getting everything he wanted, when he wanted it. Both Ming and Shaozu were relatively tolerant of his self-centered tendencies most of the time, but 'most of the time' was a pretty rare time where Tahno was concerned.
So in the end, they both decided one day, it was just easier to ignore him.
And ignore him Ming did.
Stepping nonchalantly around a silent and seething Tahno, Ming walked out into the expansive living room of the flat the three teammates shared.
Sure enough, he heard the enraged howl sound from the kitchen and within seconds, he heard the waterbender's irritated steps behind him.
"Hey! Don't you dare ignore me." He snapped.
Ming yawned tiredly, still pointedly looking in the other direction. Eventually, Tahno would grow bored of huffing and yelling, and would walk away, cursing his family as he returned to his room. This scenario had played out numerous times before, and with time, came experience. He and Shaozu knew to just wait it out.
Thing is, it usually worked. Usually.
But for some reason, it seemed that Tahno was in an especially pissy mood that day.
That, or he just really had an irritationally intense dislike of sea prunes.
Either way...
"You did not just throw a bowl of noodles at me."
Tahno, naturally, didn't respond, instead gracing his now noodle-covered teammate with a smug look that clearly said, 'And what if I did?'
Ming chuckled to himself as he calmly and collectedly wiped his face.
The inherent calm before the storm.
***********
Shaozu rubbed his shoulder tiredly as he climbed the stairs to the top floor of the building, where their apartment was located. As part of their daily training and such, Tahno insisted that they walk up to their apartment instead of taking the much more convenient elevator.
After nearly ten minutes of hiking, Shaozu finally stopped in front of the door to the wolf-bat's flat. Just as he reached for the doorknob, a loud 'bang' sounded from inside the apartment, followed by a slew of obscenities and yelling.
"Looks like Tahno's in a bad mood today..." Shaozu said to himself in frustration.
There was another crash.
Followed by more yelling. This time it sounded like Ming.
Another crash. Yelling. Something slammed against the door, hitting it with such force that the door shook, making Shaozu jump back.
"What on Earth are they doing?" He griped to himself.
There was one final crash, followed by silence.
Shaozu gulped unconsciously, but put his slightly trembling hand the doorknob regardless.
From inside, he could hear the sound of a fire starting to blaze. Followed by, as was usual of their humble abode, a lengthy string of expletives and frantic scrambling to put it out.
He also heard Tahno snap something about noodles, which was then followed by yet another crash.
"You know, Shaozu," The man began solemnly to himself, "You can walk away right now, and spare yourself the aggravation."
But despite his inner hesitation, Shaozu took a deep breath and pushed the door open anyway. He crept in slowly, looking around cautiously for any sign of his teammates.
Or at least a body.
When Ming and Tahno went at it, they really went at it.
But instead of his teammates, or -thankfully- one of their battered corpses lying in the middle of the room, Shaozu found something that made him snort, cringe, and wish death upon his cantankerous roommates all at once.
During her first year’s flying lessons she fell off her broom a record thirty-two times before they all called it a day. It’s a little known fact, that Ravenclaws can be incredibly stubborn and wholly unwilling to give (even after they sprain their wrist and bruise a rib).
