At Sugarcube Corner...
"The year was 2006. An alien spacecraft landed near the Breyer farmhouse. Tori and Kyle Breyer found a baby boy inside and raised him as their own. This was Brandon Breyer. As a kid, Brandon was exceptionally smart. He has an IQ that can rival Tails the Fox's IQ, maybe surpass it! He seemed to be living a happy life... until he discovered his true alien heritage. Feeling betrayed and lied to, Brandon was filled to the brim with rage and donned a red suit, completing his transformation into the supervillain known as Brightburn. We already knew his IQ was high, but Brightburn also has superhuman strength and speed. He can also use heat vision. He also has telekinesis, which is basically his version of Superman's ice breath. He can even mess with electronics to really give people a scare. Oh, yeah. This guy is a HORROR character. He's like Freddy Krueger and Michael Myers combined with Superman. He can also fly! He's truly a powerful foe, but he does have one weakness: his spacecraft, or rather, the material it's made out of. But other than that, if you see Brightburn, may God have mercy on your soul... because he's already killed over 274 people. He's killed Erica Connor, his crush's mother. Damn, dude! What's your problem? He also killed his uncle Noah McNichol in a car crash. Shit, dude! That's your uncle! I know you're adopted, but still! He also killed TWO policemen AND HIS ADOPTIVE PARENTS! At the end of the movie, he killed 268 people on a plane, Final Destination style. I know that these aren't the biggest feats, but it's definitely horrifying. I wasn't lying when I said this guy was a horror character. He's actually somewhat similar to Ultraman, an alternate evil version of Superman. What a coincidence. Still, Brightburn is a horror character in his own right and he has truly made a name for himself in the horror community", Ben explained.
"Wait... his spacecraft? Where's that?", Twilight asked.
"Brightburn, Kansas", Ben answered. "The question is: how are we gonna get to Earth when the scary Superman is still out there?"
"I've been working on a spell that can send us to different dimensions, like Earth. However, you'll have to hold off Brightburn", Twilight replied.
"Okay. I can do that", Ben replied. "It's hero time!" He transformed into XLR8 and sped out of Sugarcube Corner. In almost NO time at all, XLR8 stood before the remains of Twilight's castle... and the vicious supervillain from Kansas responsible for the destruction. Brightburn removed his mask, revealing his youthful face, but behind that face was a bloodthirsty monster. XLR8 transformed back into Ben as Brandon landed. The two boys stared at each other.
"I've heard so much about you", Brandon said. "A young boy wielding a powerful weapon called the Omnitrix. I was once like you. Young. Naive. Innocent. But all that changed when I discovered my true alien heritage. Now... I have a new goal. Take the world."
"We are nothing alike", Ben replied as the two boys circled each other. "I was called here to save this world from you and your twisted beliefs. It's hero time!" He transformed into XLR8.
"So be it", Brandon said. He put his mask back on. "Guess there's no use in talking to you." Brightburn sped towards his opponent, but XLR8 moved out of the way.
"Gotta go fast!", XLR8 said as he literally ran circles around his opponent.
"He's fast. Gotta anticipate where he'll go", Brightburn said to himself. Suddenly, something large and red grabbed the young supervillain and smashed him around like a rag doll. "What the..."
"Smashy-smashy!", Four Arms said. However, Four Arms wasn't strong enough to rip Brightburn apart. Brightburn broke free of the ten-year-old superhero's grip and delivered a powerful punch. "So, that's how you wanna play, huh? Let's play!" He transformed into Heatblast and ran towards his opponent.
On Earth, the humanized Mane Six and Spike, now a dog, were inspecting the wreckage that was once the Breyer house. "What are we looking for, exactly?", Applejack asked.
"A small spacecraft", Twilight answered.
"Found it!", Rainbow Dash called out. She took a piece of the ship's exterior.
Back in Equestria, Heatblast and Brightburn were still going at it.
"This is gonna get HOT!!!", Heatblast shouted as he burned Brightburn's skin. Despite being invincible, the supervillain felt pain. "How pathetic. I'll bet I can even beat you as Grey Matter." Next thing he knew, he transformed into Grey Matter.
"What the...", Brightburn said. "Whatever." He used his heat vision on his opponent, but Grey Matter transformed into Cannonbolt and deflected the lasers.
"Take that, bozo!", Cannonbolt quipped. However, Brightburn immediately delivered a powerful punch to his opponent's stomach. In response, Cannonbolt transformed into Diamondhead.
"How many alien forms do you have?!", Brightburn complained.
"10!", Diamondhead said confidently. He used his crystallokinesis to attack his opponent, buying some time to transform into Upgrade... except that wasn't the best choice.
"Uh-oh", Upgrade said. He quickly transformed into Overflow and drenched his opponent with water.
"Why don't you cool off?", Overflow asked. With the supervillain now drenched, Overflow transformed into Wildvine and ensnared his opponent with vines.
"No escape", Wildvine said menacingly. However, Brightburn broke through the vines.
"I'll squash you like the bug you are!", Brightburn screamed. Wildvine transformed into Stinkfly and flew off, but Brightburn was hot on his tail.
"Uh-oh", Stinkfly said. Suddenly, something stabbed Brightburn through the chest. Stinkfly stopped flying and transformed back into Ben. Brightburn was stabbed with a piece of his ship's material. The Mane Six and Spike had returned, and Twilight had used her telekinesis to stab Brightburn through the chest. The Princess of Friendship and the Son of Darkness glared at each other before Brightburn fell limp.
"Well... that was unexpected", Ben said. Eventually, the castle was repaired, and Ben 10 went back to Earth. The universe can now rest easy with another threat officially eliminated from existence.