Nethra's Omen

Tap up to X target creatures. Those creatures
don't untap during their controller's next untap
step. You gain X life.
{x}{x}{u}{b}: Exile Nethra's Omen from your
graveyard: Destroy up to X target tapped
creatures.
Nethra's malice manifested over the Surface, her
darkness even smothering the sun and skies.