Author's Note

I made Twilight a princess here, even though the cover art is from A Canterlot Wedding, conveniently where Twilight's wings would be is blocked off so you can't tell

The Arrival of Cooler

KABOOM!

A planet exploded in space, having just been hit with a giant golden energy ball seconds earlier.

Cooler lowered his arm.

"That was a disappointment. Nothing of value on this planet. Salza! What's the next one?"

"Ze next planet contains a land of ponies you might be able to enslave," said Salza, the blue henchman with blonde hair and a French accent. "It's a land called... Equestria!"

The Mane 6 and Spike were going on a camping trip to Rainbow Falls. Rainbow Dash got the firewood, as usual, and they were just telling campfire stories - Fluttershy was hiding in her tent for it - when suddenly there was an explosion.

The Mane 6 looked out to see three humanoid figures. One had blue skin and blonde hair. One was brown and looked amphibian-like. One was bigger with dark green skin and long dark hair.

"Look, Salza!" said the green muscleman. "I found some ponies!"

"Excellent, Doore," said Salza. "Zey'll make great slaves for Cooler."

"Hey, what's the big idea?" said Rainbow Dash.

"Cooler's taking over your world!" said the brown amphibian in a high-pitched voice.

"If you surrender, you get to live as slaves," said Salza. "If you resist, you will be destroyed."

"We could destroy YOU!" said Rarity.

"Neiz, take her by ze tail," said Salza.

The brown amphibian flew directly at Rarity. Rainbow Dash flew directly at Neiz's head and kicked. Neiz's head retracted into his neck to dodge.

"What the hay?" said Rainbow Dash.

"Retractable head!" said Neiz as his head reappeared.

Rarity blasted Neiz aside with a magic beam. Doore picked her up by the head, with a finger around her horn so she could not use magic.

"This is my Can Opener!" said Doore. Rarity felt her body go numb.

But before she could experience much of what the Can Opener could do, Applejack kicked Doore as hard as she could. Doore went flying into a rock wall. A boulder fell from the wall directly on top of Doore, crushing him.

Neiz picked up Applejack by the tail and slammed her to the ground. Then Pinkie Pie blasted him with her party cannon. Neiz quickly recovered and electrified Pinkie.

"Haha! You're being electrocuted!" said Neiz.

Pinkie stretched her tail and wrapped it around Neiz's throat, transferring the electricity to him and electrocuting him. Neiz's fried body hit the ground.

"Zis won't be easy," said Salza.

"It will for me," came a voice. The ponies and Salza turned to see Cooler walk in. He was a purple humanoid with a long lizardlike tail.

"Who the hay are you?" said Rainbow Dash.

"I'm Cooler, the ruler of this universe. I will rule Equestria! I will fight the rainbow pony. She seems to be the most powerful. Salza, take the purple pony."

Salza shot an energy blast at Twilight. Twilight countered with a magic blast of her own, which overpowered Salza and vaporized him.

"So, she's powerful too," said Cooler. "I'll take you both on at once!"

"What about the rest of us?" said Pinkie Pie.

"You'll get your turn when I'm done with them."

"Ain't gonna happen!" said Applejack. "We're fightin' all at once!"

The Mane 6 jumped at Cooler, but he quickly shot finger beams to knock Applejack, Pinkie Pie, Rarity, and Fluttershy aside, which knocked Fluttershy out.

Cooler shot an energy blast at Twilight. Twilight entered another beam struggle with him, but he overpowered her, blasting her into a wall. Rainbow Dash flew circles around Cooler, but he whipped her away with his tail.

Twilight and Rainbow Dash recovered and flew into the air, Twilight shooting more blasts at Cooler. Cooler flew up after them.

"How can these guys fly without wings?" said Rainbow Dash.

"Many of us from other worlds can!" said Cooler.

They fought in the air for a while, and then Cooler hit Twilight with a Death Beam, sending her crashing to the ground, before whipping Rainbow Dash to the ground with his tail.

Cooler touched down on the ground and wrapped his tail around Rainbow Dash's throat. Rainbow Dash grabbed his tail with both her hooves.

"If you let go, your head will pop off like a champagne cork!" said Cooler.

CHOMP!

Cooler felt a sting on his tail. He looked to see Applejack biting his tail.

Rainbow Dash chuckled as she felt Cooler's grip loosen. "That pony loves biting tails!"

Applejack bit as hard as she could, but Cooler barely felt anything, for pony bites didn't hurt very much. Applejack spun Cooler around and threw him into a tree, which fell on top of him. Twilight quickly blasted Cooler, and then she and Applejack got clear as Rainbow Dash flew directly at him from above, causing a rainbow explosion on contact.

When the smoke cleared, Cooler stood up, wounded but still alive.

"So, you are a match for me... in this form!" he said. "But I have a form beyond this!"

Cooler transformed into a form that looked similar, but more spiky, with several horns on his head.

"Not very impressive!" said Rainbow Dash, and she flew at Cooler, but he whipped her aside with his tail.

Twilight shot her most powerful magic blast at Cooler, but he wasn't even affected, and punched her away.

Applejack kicked Cooler. He barely felt it, and kicked her away.

Pinkie ran over to Twilight and turned her tail like a handle, causing her to shoot lasers from her horn. They bounced harmlessly off Cooler. Cooler grabbed Pinkie by the tail and slammed her to the ground, knocking her out.

"With Pinkie Pie and Fluttershy unconscious, we can't use Rainbow Power!" said Twilight.

Rarity ran in front of Cooler and whipped her tail back and forth.

"Is this supposed to distract me?" said Cooler.

Applejack ran up to Cooler and kicked his shin. He hopped around on one foot.

"Why is it you can hurt me now?"

"Tail Whip lowers the enemy's defense," said Applejack.

"How do you know that?" said Cooler.

"Applejack knows everything there is to know about tails," said Rainbow Dash. "She took a tailology course once."

"Then she'll know what my tail can do!" said Cooler, who wrapped his tail around Rarity's throat. Applejack bit his tail, causing more pain this time, and forcing him to relinquish her. Cooler turned around to blast Applejack.

"NOT SO FAST!"

Fluttershy flew between Applejack and Cooler so that she was facing Cooler, and gave him the Stare! Cooler stood frozen, unable to move.

Rainbow Dash bit Cooler's tail and flew as fast as she could into the air. As soon as she was faster than the speed of sound, she did the Sonic Rainboom, causing a rainbow shockwave while leaving a rainbow trail behind her.

"LET ME GO THIS INSTANT!" said Cooler.

Rainbow Dash did not respond, nor did she listen to him. Once she was close enough to the sun, she came to a sudden stop and released Cooler, sending him flying straight into the sun.

Twilight, Fluttershy, Applejack, and Rarity waited for Rainbow Dash to return. Eventually, there was another Sonic Rainboom, and Rainbow Dash returned.

"Where's Cooler?" said Twilight.

"In Tartarus," said Rainbow Dash. "We won't have to worry about him again!"

Or would they?