When this Case enters the battlefield, investigate (To investigate, create a colorless 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 (This creature can't be blocked except by creatures with flying or reach.) in addition to its other types.