Sena, Blessing of Corruption

When Sena enters the battlefield, create
two 2/2 black specters with
"corruption points". when a creature with
a corruption point is under your control,
Sena gains Indestructible and Hexproof.
{t}{3}{b}{u} as an additional cost to this ability,
you lose 1 life. target a creature your opponent
controls, you gain control of it, and give it
a corruption point.