Seriphea, Underground Queen

Tap an untapped black creature you control:
Put the top card from target players library
into their graveyard.
Tap three untapped green creatures you control:
Exile target creature card from a graveyard.
Create a 1/1 black Skeleton creature token.
Tap five untapped Skeletons you control:
Put target creature card from a graveyard
onto the battlefield under your control.