Winter Soldier: Captain America's sidekick Bucky was believed lost over the Atlantic during World War II, but his frozen body was found by a Soviet submarine. Brainwashed and given a robotic arm, he became the USSR's greatest assassin.

Marvel's Falcon: Sam Wilson was once Captain America's sidekick, but it was the Black Panther who gave him his fantastic flying harness, and the Red Skull who gave him a mental bond with his falcon Redwing, as well as other birds.