First Seen In: Fear Itself #7.
The origins of this suit of armor aren't are as far-fetched as some others in Iron Man's history - an Asgardian makes a play for Earth, and the planet's heroes must stop the assault. With a little Asgardian magic, of course. In the "Fear Itself" crossover event, it wasn't the trouble-making Loki (and given his apparent redemption in Thor 2, his days as a pure villain may be in the past) but Odin's brother, 'The Serpent' setting his sights on the throne of Asgard.
To give humanity the best chance, Iron Man took a trip to Odin's realm seeking back-up. While Odin wouldn't give it, he did grant access to the skills of the dwarves of Svartalfheim (a realm soon to be explored in Thor: The Dark World) in crafting weapons imbued with magical energy. While he was there, he gave his own armor a few... upgrades.
The dwarves coated Iron Man 's standard armor in a layer of uru - the fictional metal from which Thor's hammer was also forged - and magic from Odin. Dubbed the 'Iron Destroyer' armor by Stark due to the physical resemblance to the Asgardian bodyguard seen in Thor (2011), the suit merged technology with magic in a way only Iron Man could pull off.
All things considered, it's actually believable that the Iron Man and Thor franchises could be linked via Tony's armor. Besides the Iron Destroyer suit being capable of battling magical and mystical enemies (which wouldn't be out of place in 'Phase Two') Stark has also used Asgardian magic to fuel the 'Thorbuster' armor when the god of thunder went rogue. But if we only get one, we'll take the spikes.