There’s not a whole lot to add to this. Most people know the story. Perseus with sword and shield, stalks in after Medusa. He uses the reflection of his shield to keep from becoming petrified himself—which shows his cleverness—and slices her head off. Easy-peasy when you’ve got a Bat-shield, Bat-sword, and Bat-pouch. Hey, is any joke too far after the unfortunate Bat-credit card in Batman and Robin?
Now, we have a tesseract situation. It’s not the first one in Greek myth since Athena sprang out of Zeus’s skull fully-grown. But out of medusa’s neck flies a fully-grown Pegasus. Don’t ask me how. As one of my mythology classes put it, “Because Greeks.”
Now Perseus doesn’t ride Pegasus. He doesn’t need to. He’s got sandals with wings on them. And, sorry, Disney fans, Hercules never rides Pegasus. Instead a hero by the name of Bellerophon will tame and ride Pegasus, but that’s another myth.
So what else is there to say about this part of the myth? Well, death is not the end of Medusa’s curse. Her head is hideous and fully capable of petrifying anyone post-mortem. Unless they are using a reflection to look at her, they’re stoned, and not in that way. Perseus will go on to use this weapon quite prolifically.
The effects are also permanent. There is no cure for someone turned to stone. It works against anything capable of seeing the head, man or monster. The only thing we don’t know is if it affects the gods. Given their power to change form on their own, I doubt it would do anything to them, but we don’t have any concrete proof one way or the other, but I would file it under “doubtful.”
This is, in essence, the nuclear weapon of the ancient world.