Originally posted by JakeTheBank
I had one:
Superman/Thor: Last Son of Asgard: Not a typical crossover, but more of a what if/elseworlds story. Essentially, the premise is that during the last days of Krypton, Jor-El sends his infant son via rocket to escape the doomed planet, but instead of reaching Earth, baby Kal is instead enveloped in a strange extra-dimensional storm caused by the overloading of various high tech Kryptonian machines, effectively sending him to Asgard instead.
Kal-El crashes in front of the royal palace of Odin, and after some consideration, is brought into the family, raised alongside the likes of Thor and Loki. Curiously, in spite of him being a mortal, Kal-El has raw physical might that rivals even the mightiest of gods, which endears him to both Thor and Odin. And while he's not proficient in magic (and even seems to be more adversely effected by it compared to the Asgardians), earns the begrudging respect of Loki due to his intellect and wit, being the one person who seems to be able to compete with the trickster mentally. Loki plots to remove Thor so that he would be next in line for the throne, but Kal always seems to get in the way, thwarting his plans. Eventually, Loki discovers the craft Kal arrived to Asgard in, and with some experimenting, activates the crystals inside, effectively learning all there is to know about Kryptonians, something that was previously only known by Odin.
The series would eventually lead to Kal accepting Thor's punishment of banishment to Earth to appease the Frost Giants, a scheme orchestrated by Loki in secret. Incensed that Kal's accepting Thor's punishment, Loki weaves a special spell, having deduced that his strange powers are given to him by sunlight, effectively cutting his body off from absorbing it. As such, Kal is powerless when he's sent to Earth and sustains a brutal leg injury in the process.
Eventually, the story reaches the point with Ragnarok being set in motion as Kal struggles to live among human mortals, making ends meet as a lame legged journalist named Clark Kent. The Twilight of the Gods finally happens, but Odin manages to save both his sons the only way he knows how: stripping them of their respective divinity and sending them to Earth with altered memories, subtly shifting reality in the process. Thor is given the alter ego of Donald Blake, and Loki is given the alter ego of Lex Luthor. In the process, Mjolnir falls from Asgard, hitting Earth.
While on a trip to Norway covering a international summit of LexCorp technology, Clark - working for the Daily Planet alongside Lois Lane - is forced to act when the LexCorp tech goes haywire, causing chaos and devastation, namely in the form of unleashing a horde of Frost Giants! In the crisis, Clark and Lois fall deep into a cave, which is threatening to collapse at any moment. Donald Blake, on scene as a medic, is drawn to help the civilians as best as he can, while Lex Luthor (having secretly planned the whole thing) is impressed with the results and oddly enough, takes a personal sense of joy from watching the chaos. The two briefly glance at one another, almost feeling a sense of recognition before dismissing it.
In the cave, Clark, desperate to save Lois even at the cost of his own life, finds a stick, using it to shift the rocks just enough for Lois to escape, but not before triggering a collapse. But as the cave drops, the stick suddenly transforms into the hammer, Mjolnir, effectively transforming Kal from his powerless mortal self to his fully powered Kryptonian body. Easily escaping the cave and saving the day, Kal realizes that if Mjolnir fell to Earth, then something dire has happened to Asgard. Resolving to put both his Kryptonian powers and the mystical hammer to good use, Kal becomes Earth's newest and greatest champion, using Mjolnir to cleave through dimensions, returning to the ruins of Asgard. While there he discovers the fate of both his Kryptonian home and his adopted one, resolving to honor both as well as the world of mortals.
Meanwhile, the transformation of Mjolnir triggers in Donald Blake all his previous memories as the God of Thunder and does the same for Lex Luthor in his previous life as the God of Mischief. Eventually Kal and Donald (Thor) meet one another as brothers. The Odinspell placed on Blake allows him to lift Mjolnir, but doesn't trigger his transformation back to Thor. Nevertheless, Blake offers to aid Kal as best as he can as an expert on Asgardian lore, confident that the rest of the gods live among mortals and can be found. He also notes that if the gods somehow survived Ragnarok, so too could their enemies.
The story ends with Lex Luthor attempting to merge both technology and ancient magics to undo the Odinspell to return to his godly formand get his revenge on both Kal and Thor.
I had a lot of time on my hands, apparently.
It's an interesting idea.
I think I would have gone in different directions with it but definitely sounds thought out and good. My favorite part was the idea of Loki becoming Lex. It seems oddly fitting for him.