TVTropes on myth!Loki:
♦ Was Loki imprisoned for killing Baldur, or was he imprisoned for calling the gods out on crap they were actually guilty of? Depends on which story you read.
♦ Loki and Heimdall. The very first story they costarred in set them against each other. Like Thor and Jormungand, they are also destined to kill each other in Ragnarok.
♦ Many adaptations (probably thanks to Marvel) tend to set up Thor and Loki as arch-enemies. While they butted heads once in a while (Sif's hair was certainly a Berserk Button for Thor), they were more friends than enemies, and often traveled together.
Cain and Abel:
♦ Thor and Loki become this in Christian retellings of Norse myths (while Loki was Odin's brother in the original myths) as well as in Marvel Comics.
♦ Whenever the gods need to put the blame on someone, they grab Loki and threaten him with torture and death if he doesn't put the situation right. Granted, often Loki was responsible for or at least involved in the thing that went awry in the first place, but still...
♦ In one story, Loki makes a bet with some dwarves and offers them his head as a wager — an expression for "my head's weight in gold" — as his part of the bargain. When they win and claim his actual head, he argues that since they can't take that without also cutting his neck, the deal is void. The dwarves content themselves with sewing his lips together earning him the nickname Scarlip, and the scars remain in his various forms.
Fate Worse than Death:
♦ The gods can't kill Loki for what he did to Baldur on account of Odin having adopted him. Thus, they instead bind him in chains made from the entrails of his son, whom they murdered, and allow a snake to drip venom on his face for eternity. Loki's loyal wife Sigyn collects the venom in a bowl most of the time but she eventually has to empty it, allowing the venom to drip and causing him excruciating pain. His thrashing around caused earthquakes.
♦ Loki turned into a mare (and got pregnant!)
♦ Loki does this to himself when he's faced seemingly-impossible task of making Skadi laugh. He ties a rope to his own testicles, then ties the other end to the beard of a goat. Hilarity Ensues.
Heterosexual Life Partners:
♦ Thor and Loki, at least in some stories. In others, not so much.
♦ Odin and Loki, who are blood brothers.
Hijacked By Jesus:
♦ The story of Loki getting Baldur killed is Hijacked By Jesus. Originally (as shown in Poetic Edda), it was only hinted (in an insult of Frigg by Loki himself) that Loki was guilty. It was when he gravely insulted every single one of the gods they tied him down and fed him poison. The two stories were then merged and expanded by Snorri Sturluson to make Loki look like a Satan figure.
♦ Like Hel, Loki gets associated with Satan. In some myths, he's a contriver of trouble, a trickster, and a total jerkass, but still not all that bad of a guy as he saves the day a few times and once in a great while goes out of his way to be nice. In later, post-Christian stories, he's Handwaved as the cause of anything wicked, with no explanation as to why or how he'd managed it, and then he's the cause of the end of the world.
♦ Sleipnir is the biological child of Loki and a stallion called Svadilfari. Loki was shapeshifted into the form of a mare (a female horse) at the time. A mare who happened to be in heat, to lure away the stallion. However, getting pregnant had not been part of Loki's plans, and it owned him the nickname of "horse-mother".
♦ The unspecified number of children Odin and Njorth accuse Loki of bearing in the Lokasenna.
Hostage for MacGuffin:
♦ This one happened to Loki a lot, even at the hands of other gods, and caused - among other things, the cursing of Andvarinaut, the creation of Thor's hammer, and later on its theft. Thor even did it to Loki over a cute little prank Loki pulled on Thor's wife.
♦ In the Lokasenna, Odin says Loki went around disguised as a milkmaid for awhile, and according to both Odin and Njorth, he's given birth to multiple children. It doesn't get any more elaborate than that.
Pet the Dog:
♦ In "Loka Táttur," after Odin and Honir fail to answer the prayers of a farmer to keep his child hidden from a bad-ass troll, they give up completely. Loki, ever the Determinator, succeeds in protecting the kid and slays the troll, and is rewarded by the boy's parents with a big hug. Awww.
Really Gets Around:
♦ Freya gets around with anyone, while Loki gets around with anything.
With Friends Like These:
♦ You would think that, after a while, the Aesir would actually figure out that perhaps Loki could use some help. No wonder he turned against them eventually.
You Can't Fight Fate:
♦ Some retellings of Loki's role in Baldur's death use this to explain Loki's actions. After devouring the heart of a witch with the power of prophecy, he saw that he was destined to suffer a horrific punishment at the hands of the other gods before dying in Ragnarok. Since Loki knew You Can't Fight Fate, he figured he might as well do something to earn that punishment and make the other gods suffer.
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