Believe it or not, there was a time when Wonder Woman and Supergirl were forced to fight to the death. It all takes place in Wonder Woman 177 when some loser from another galaxy wants the ultimate supreme queen.
Some robot dictator thing name Klamos needs a queen, so his followers such the galaxy. What they find is Wonder Woman fighting some random women in black suits shooting fireballs or something. Whoever she is fighting apparently does not matter because the background is solid green and there is no context. Wonder Woman is easily captured by her spectators by pretending to be a bum and giving her some handcuffs disguised as a necklace. Confused? Yeah, me too.
The same aliens also find Supergirl, who happened to be fighting scuba-divers underwater. As if she was not powerful enough, she still had to take advantage of the inertia while kicking some poor schmuck in the side of the head. She even swings around a chain. Yes, underwater. She is quickly captured as well by conveniently turning the entire sun into a red sun, which takes away her powers.
The result is Wonder Woman vs Supergirl, as they are forced to either fight to the death, or let earth be destroyed by space ships. Because, ya know, that has never been attempted before in comics I guess. The whole Wonder Woman vs Supergirl scenario quickly becomes entertaining as Wonder Woman begins to strangle Supergirl in a head-lock. Supergirl gets on top of Wonder Woman and they begin punching each other in the face.
In the end, Supergirl wins, but really it was a staged ploy to stop the villain. I mean, you did not think they were really going to fight to the death, did you? Wonder Woman 177 was the last issue before DC decided to make her lose her powers and outfit, basically completely destroying the character and all of its followers along with it.
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