Long ago in a newly built and not-so-shiny Asgard; Odin had a problem. He had a nice city built for his golden Aesir, but no wall to protect them from their enemies! He had to think of something right quick or else the Jotnar would come and bring eternal Christmas to Asgard, which if you watched Fairly Odd Parents, was actually not a good thing.
Odin puzzled over this problem until his puzzler was sore, but still he could only think of one way to get the wall built before eternal Christmas befell Asgard in a haze of jingle bells and Ho-Ho-Ho's. He had to find a carpenter with crazy mad skillz who could build faster than a fly's lifespan. The problem arose when Odin realized the only crazy mad skilled carpenter of this caliber was a Jotun. Odin realized he had to be sneaky so he called upon the aid of his little Jotun-turned-Aesir-prince, Loki.
Loki, ever eager to prove himself to Odin, was delighted that the All-Father chose him to trick the wall-builder. When the carpenter wagered he could build the wall in three summers in return for the Goddess Freyja's hand in marriage, the sun, and the moon, the Aesir laughed it off and told him,
"Okay cool story bro, but if you can't do it by the time summer starts, you won't get paid."
So the builder got to work. He asked the Aesir if he could use his horse to do the heavy lifting, and seeing nothing benefiting the builder if one horse was at his disposal, Loki agreed.
"Why not?" He shrugged.
Loki should have considered the carpenter's crazy mad skillz were why he was chosen for the job. With the carpenter and his equally crazy mad skilled horse Svaldifari working together, the wall was nearly complete by the end of three seasons. With only three days and three nights remaining until the time limit ran out, and the only thing needed finishing was the entryway, Odin flipped his shit. He took Loki aside and went off on him saying,
"Son, I am disappoint. If you can't get trick this guy into not finishing my wall, I am going to do something bad and very, very not good."
Considering Odin was the guy who sewed Loki's lips shut for getting him presents, Loki was not going to sit on his ass and figure out what 'very, very not good' meant.
Being a shape-shifter, Loki was able to turn himself into a sexy lady-horse who was conveniently in heat. He strutted up to Svaldifari and flicked his sleek black mane back and batted his eyelashes. Svaldifari saw Loki and went,
"Damn girl, yo booty fat!" And thus, the chase was on. Loki managed to get himself stranded alone in the woods with a horny horse, and if you have any streetsmarts at all, you know where this is going.
So after three days and nights of fonduing, Loki limped back to Asgard with a sore ass and a pregnant belly. The builder didn't have enough crazy mad skillz to finish the wall by himself, so Loki pretty much got a free wall for Asgard. Obviously that means he's a high class hoe. Oh wait, I'm sorry, Escort is the politically correct term. (We all know he's a slut.)
Nine months later, baby Sleipnir was born. He had eight spindly legs and somehow that made him faster than any horse ever born, despite obvious anatomy flaws. Odin looked at Loki and his son and shook his head.
"Loki, you are one sick bastard. But your son is a pretty pony, so I'll just yoink him from you and make him my horse-slave. Kthnx bai." He said while Thor held his little brother back from ripping Odin's other eye out.
"Loki, y u mad? It's just a horse!" Thor tried to consol him. Loki gave the most epic bitchface ever created and said,
"And you wonder why eons from now when I find out my Frost Giant heritage, I hate your guts?" Thor didn't quite catch Loki's words so he blinked and said,
"You say something, bro?"
"No, Thor. Go get your fabulous hair did and leave me to brood in the corner and sing songs from Evanescence." Loki sighed.
The end.