My sister was a mirror twin. They shared a placenta, and she developed reverse of her twin (they believe this happens after a very late split) and it came with a huge price. Her twin, the one that was developing with organs in the usual place, ended up with her blatter and organs outside her body. Initially they thought they lost both twins.

When she was born, my mom didn't get to see the aftermath of what happened to the other baby, she was unconscious. I don't think my dad did either. But my sister is alive, happy, and healthy despite a lot of struggles along the way.