Believed destroyed at an abandoned Nextgen storage facility, West Virginia
None; (Formerly) A.I.M., Red Skull, Sub-Mariner, unnamed fisherman, Thanos, Project: PEGASUS, Victorious, Hate-Monger, Korvac, Grandmaster, Doctor Doom, Magneto, Magus, Goddess, Aleksander Lukin, Mole Man
Few items in the universe could ever compare to the sheer power of a Cosmic Cube. The power within the Cube allows whoever wields it to literally reshape reality around him. Virtually anything is possible, from the raising of mountains and commanding the power of the elements to opening dimensional portals and transforming your enemies.
The first Cosmic Cube created on Earth was the result of A.I.M.'s experiments with "x-element" energy, experiments that necessitated the creation of M.O.D.O.K. in order to handle the near-impossible influx of information involved. So powerful was the Cosmic Cube that MODOK was driven insane. The Red Skull, allied with A.I.M. at the time, coveted the Cube for himself and surreptitiously arranged to steal it, banishing the Cube's Keeper to another dimension the minute he gained possession of it. A.I.M. alerted Captain America, who confronted the Skull, and despite the Skull's near-omnipotence, managed to use the Skull's overconfidence to shake the Cube from his grasp. The tremendous energies already released sunk the island they were on, and the Skull and the Cube were believed lost. (The Sub-Mariner recovered the Cube only to lose it to the ocean after an attempted revenge against the Avengers.)
A fisherman who discovered the Cube used it to transform his small village into a thriving community, but the Red Skull was waiting for news that could only be attributed to the Cube. He and his Exiles stole the Cube, and the Skull again used it against Captain America. Among his machinations were switching bodies with his archenemy and transforming Snap Wilson into the Falcon. The Skull was stopped, however, by A.I.M. and M.O.D.O.K., who had created a Catholite Block that appeared to dissolve the Cube.
MODOK managed to retrieve the Cube, and many others would content for its possession. But it was Thanos who claimed it. Realizing its potential more than any of its previous users, Thanos pompously challenged the Avengers and Captain Marvel (Mar-Vell) directly before absorbing the Cube's energy within himself. Becoming convinced that he no longer needed to grasp the Cosmic Cube to wield the power, he discarded it, and Captain Marvel used the Cube to restore reality, apparently burning out the Cube entirely.
The Cube was remanded to Project: PEGASUS for analysis, where unknown to all it influenced the development of Aquarian. It often wound up in the hands of villains who discovered its existence, such as Jude the Entropic Man and by agents of the Serpent Crown, but the Cube's true secret was more fantastic than anyone could have guessed.
A.I.M. tried to recapture the Cube only to be confronted by Captain America, and the Cube itself began twisting reality uncontrollably. The Cube was intelligent and trying to break free! In fact, the Shaper of Worlds arrived, explaining that the Cube was an incubator for a higher intelligence, and he was one such being, having evolved from a Cosmic Cube developed by the Skrulls. He took the Cube with him into space, where it finally hatched into the being Kubik.
The Red Skull tried to re-create the Cosmic Cube by kidnapping its original inventor. Allied with the Hate-Monger (Adolf Hitler) at the time, the two squabbled over its creation, and the Hate-Monger ended up trapped within the Cube after interrupting its development. This Cube became a target for a time-travelling Michael Korvac, who manipulated Captain America and the Red Skull to vie for its possession and snatching it away for himself. Korvac used the Cube to create a reality under his dominion, but Captain America survived to overthrow him. Korvac was forced to change history so that this reality never came to pass, but in the process lost the Cube. The Grandmaster later manipulated the Avengers and a team of heroes from another universe to compete for the Cube, using it and other objects of power to stop both universes from merging.
Other Cosmic Cubes have been created over the years, including one spearheaded by Doctor Doom (Victor von Doom). The X-Men attempted to stop him, in the process the Red Skull also intervened with an imperfect Cube of his own. Reality had become so distorted by this time that it took the sacrifice on one of the Skull's followers to claim the Cube and restore reality. This Cube was appropriated by the Magus (Adam Warlock) and used in conjunction with other "Cosmic Containment Units" to attempt to subvert reality, and when he failed due to Adam Warlock and an assemblage of heroes, the Goddess used them for similar ends. With her defeat, the Cube and other Units were rendered useless.
Perhaps this Cube was among those Cubes and Cube fragments used by the Red Skull in re-creating yet another one. The Winter Soldier, on behalf of Russian general Aleksander Lukin, stole the Cube after killing the Red Skull, but the Skull was able to transfer his consciousness into it before he died. This Cube was only partly functional, as it drained the life of its user bit by bit as it was used. Lukin wanted to re-power the Cube through exposure to enormous explosions, and he set in motion various schemes to seize control of corporations such as Roxxon Oil, merging them with his Kronas International corporation. However, he soon realized that his life was not the only thing at risk-- the Skull began to exert more and more influence from within the Cube. Lukin bade the Winter Soldier store the Cube, but the Soldier was interrupted by Captain America and the Falcon. Captain America used the Cube to make Winter Soldier remember and freeing him from the effects of years of Russian reprogramming. When his memories came back the Soldier crushed the Cube in his rage and apparently destroyed it, but before that it teleported him to old army base where was sent to war so long ago.