Case of the Lost Witness is a mythic Enchantment — Case card from Alchemy: Murders at Karlov Manor (YMKM), collector number 4.
When this Case enters, conjure four cards named Fblthp, the Lost into your library, then shuffle. Draw a card. To solve — You control a legendary Homunculus. Solved — You may look at the top card of your library any time and you may play lands and cast spells from the top of your library.