J&K, the Aeons Torn

Flash, Flying
J&K, the Aeons Torn can't be countered.
When you cast J&K, take an extra turn.
When J&K enters the battlefield, counter target
spell and deal X damage to any number of
creatures, planeswalkers, or players where X is
that spell's converted mana cost, then each
opponent discards that may cards.
Together, babe, we are unstoppable!