Dark Dark Boo
From the Super Mario Wiki, the Mario encyclopedia
Dark Dark Boos are shadow versions of Dark Boos. They made their debut in Super Paper Mario, only appearing in the Flopside Pit of 100 Trials. They are the strongest variation of Boo in the game. Their attack pattern greatly relies on the Flip, a technique they keep using in an attempt to use a sneak attack on Mario and co.
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