MKM-80 Case of the Stashed Skeleton

When this Case enters, create a 2/1 black Skeleton creature token and suspect it. (It has menace and can't block.)
To solve - You control no suspected Skeletons. (If unsolved, solve at the beginning of your end step.)
Solved - , Sacrifice this Case: Search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.