Skull of Gul'dan

Indestructible.
{t}, Sacrifice Skull of Gul'dan: You lose 5 life.
Choose a creature you control. That creature
gains +5/+5, Indestructible, and attacks each
turn if able. During your upkeep, put a -2/-2
counter on chosen creature. If chosen creature
has toughness 0 or less, exile it.
Exile Skull of Gul'dan.
Once used to close the Dark Portal, the Skull of
Gul'dan was used for other purposes...