Tempt to Darkness

Cast this only when a creature an opponent
controls dies. Take control of a non-black
creature they control with power lower than the
power of the creature that died.
"That's how it starts; the hatred. The outrage.
Watching helplessly as a loved one dies. This is
Erythnul's secret. Revenge is what turns good men...
cruel." -Boren, Cleric of the Bloody God