Tiny Baby Costume with Black Cats Toddler size

Purple & Black. The Body is black with Black Tole sleeves and, a ruffle at the wrist, Purple Tole Puff sleeves, and Purple Tole Skirt has black glitter Cats & black underskirt with Zig Zag bottom. Trim at the neck I don't see a size. There is a battery & wires, never saw this have no idea what its for.