When this Case enters the battlefield, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

To solve - You control three or more artifacts. (If unsolved, solve at the beginning of your end step.)

Solved - , Sacrifice this Case: Put four +1/+1 counters on target noncreature artifact. It becomes a 0/0 Bird creature with flying in addition to its other types.