The Soul Stone

As an additional cost to cast this spell, exile a
creature or Planeswalker.
{x}{t}Choose one —
•Up to one target creature gets -X/-X until end
of turn. If X is 5 or more, return a creature card
with mana value X or less from your graveyard to
the battlefield tapped and attacking.
•Target noncreature artifact you control
becomes an artifact creature with power and
toughness equal to X until end of turn.