Case of the Filched Falcon

(U) 

When this Case enters the battlefield, investigate. (Create a Clue token. It's an artifact with "(2), 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 — (2)(U), 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.

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