Kel'Thuzad, Recruiter of Death

Sacrifice a creature: Kel'Thuzad, Recruiter of Death gains +1/+1
When Kel'Thuzad, Recruiter of Death becomes a 6/6 or greater sacrifice him, be hecomes Kel'Thuzad, Leader of the Cult, he becomes an Undead Skeleton in addition to all other types. Kel'Thuzad, Leader of the Cult can be tapped to counter target spell, the caster takes damage equal to the total mana cost.