You always wanted to fly, Kent! Now it's your chance!
„
~ Corrupted Superman making fun of Clark Kent before throwing him into the trash compactor
Corrupted Superman is a major antagonist in the movie Superman III and is somewhat unique (at least at the time) as being a villain that is actually a part of Superman himself - his selfish and suppressed evil half taken form.
He was portrayed by the late Christopher Reeve, who also played his good counterpart.
History
Corrupted Superman committed small-scale villainy compared to many of the Man of Steel's enemies but was perhaps one of the greatest due to the fact that Superman had to face his own inner-demons and literally overcome his dark side in order to regain control over his life.
Some of the things Corrupted Superman did were extinguish the Olympic Flame, straighten the Leaning Tower of Pisa and ripping open an oil tanker so that the contents would fall out and pollute the surrounding oceans - as stated before these were casual acts of vandalism but soon mounted up as the public began to see Superman as a super-powered thug rather than a protector.
Corrupted Superman was the result of exposure to Kryptonite (which normally weakens Superman, however the Kryptonite used in the movie was synthetic and thus he was corrupted rather than weakened).
In the end Superman defeated his Corrupted counterpart via splitting into two beings, the Corrupted Superman and the seemingly mortal Clark Kent - however Clark Kent proved to be stronger than the Corrupted Superman and despite numerous attempts to crush him using industrial machinery Clark soon caught up to his Corrupted clone and strangled him, causing him to vanish.
As the corruption wore off Superman wasted little time in undoing the varied acts of vandalism his evil-half had committed.
Trivia
In the Arrowverse show, Supergirl in the first season episode "Falling," the corruption of Kara Danvers/Supergirl was a nod and tribute to this evil version of Superman. She even had the same mannerisms like when she flicked nuts in a bar and shattered glass liquor bottles. Both were even corrupted by badly conjured Kryptonite which instead of killing them, brought out their darkest natures.
