10 Best Times Superheroes Became Villains

4. Bucky - The Winter Soldier

2005 was sort of a year of coincidences for Marvel and DC, as both publishers elected to resurrect long lost sidekicks as violent, gun-toting figures to come back and haunt their former partners. For DC this was Jason Todd, who was resurrected as the Red Hood in the wake of Infinite Crisis. As for Marvel - who arguably had the more successful resurrection of the two - that figure ended up being Bucky Barnes, Captain America's long lost sidekick thought lost as World War II neared its climax.

Ed Brubaker and Steve Epting's run on Captain America proved to be highly influential as it progressed, but by far its most important arc revolved around Bucky's return. Together, the creative duo fashioned a new legacy for the character that revealed how Bucky had been recovered by the Soviet Union, brainwashed, and turned into an assassin.

It thusly falls to Steve Rogers to bring him back, with Bucky's turn being the catalyst that inspired the definitive image of the pair's enduring friendship.

While Bucky would eventually turn good again, his past as a brainwashed assassin has gone on to inspire dozens of fascinating stories, set both in the past and the present Marvel continuity.