Knothole of Forbidden Memories

{b}{g}: Choose an option that hasn't been chosen. If every option has been chosen, exile Knothole of Forbidden Memories, then return it to the battlefield transformed under your control.
-You gain 5 life.
-Put 2 +1/+1 counters on target creature.
-Draw a card.
-Put 2 1/1 colorless Servo artifact creature tokens onto the battlefield.
(Transforms into Boo Radley, the Forgotten)