SCP-012

When SCP-012 enters the battlefield, sacrifice target creature.
SCP-012 does not untap during your untap step.
{t}{x}{b}: Tap target creature with converted mana cost of X. The creature does not untap until SCP-012 is untapped. When SCP-012 untaps, destroy the tapped creature.
{2}{b}: Untap SCP-012