Colm of Coldheart

When Colm of Coldheart enters the battlefield, you may sacrifice another creature. If you do, draw X cards and tap X target permanents, where X is that creature's converted mana cost.
{1}{u}{u}{b}: Tap up to two target permanents. For each permanent tapped this way, its controller loses 1 life.
Sarkhan was the first to fall as Tarkir froze.