The Destroyer

The Destroyer was made by the dwarves for Odin.  When a sentient's spirit is placed within the armor by mystical means, it becomes a juggernaut (no relation) of destruction, virtually unstoppable.

The armor was recently stolen from Odin by the Enchantress while in the service of Surtur, and used against Thor and the Avengers.  After it was defeated, Iron Man locked it safely away in the vault beneath the Avengers Mansion, in a special containment unit.