Yu, Seeker of Truths

Melee
Whenever Yu, Seeker of Truth and at least two
other creatures attack, gain 1 life and investigate.
Creatures your opponents control lose hexproof
and can't gain hexproof until end of turn.
Clues you control have "{g/u}{g/u}, Sacrifice this
artifact: Draw a card. Creatures you control gain
+1/+1 until end of turn."