She once tried to become the most powerful in the universe by taking on Dark Tails, the officially most powerful being ever. After five minutes, Dark Tails put her in a coma. She never emotionally recovered from her defeat, and now mentally thinks that Dark Tails doesn't exist. Exactly 1337 days after this, Dark Mandy met Dark Tails again and Dark Mandy's head exploded from confusion. Dark Mandy survived the explosion due to her head regenerating somehow, and she then screamed "Ah! It's the thing that doesn't exist!" and ran away in fear.