Creature — Human Cleric Shaman 1/1, 1B (2)
Common
{T}, Sacrifice a creature: Target creature gets +2/+2 until end of turn.
{1}{U}{U}, Sacrifice a creature: Counter target creature spell.
"The Shamans of Marit Lage do her bidding in secret, but they do it gladly."
—Halvor Arenson, Kjeldoran Priest
Illus. Cornelius Brudi

4/1/2008: A "creature spell" is any spell with the type Creature, even if it has other types such as Artifact or Enchantment. Older cards of type Summon are also Creature spells.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander