Costume is a entity that is resembles a man wearing a Miles 'Tails' Prower costume albeit with a much broader appearance, wearing black shoes, alongside light gray gloves. And black fur with grey tips of the tails, grey muzzle and grey chest fur, and lastly, hollow eyes. It is unknown if this is actually Mike Robertson, a representation of him, perhaps a metaphysical variant, or this entity might be a copy summoned by Stanley to kill others. Only Costume itself knows on what it actually is.