TRESNIOK, COUPLED MINDS

Menace, first strike, haste, toxic 2
-when tresniok enters the battlefield
target opponent mills ten cards
-until the end of your next turn
you may play those cards
-tresna, a mythical and elusive phyrexian beast
has taken host to a legendary auriok blacksmith
giving tresna the power to shape metals...
at the cost of the auriok's sanity.