Blood Vendetta

{t} Destroy target creature. Place a feud counter
on Blood Vendetta, and that creature's controller
gains control of Blood Vendetta. Activate this
ability only any time you could cast a sorcery.
At the beginning of your end step, if Blood
Vendetta has four feud counters, sacrifice it.
"And the continuance of their parents' rage,
Which, but their children's end, naught could remove"
-William Shakespeare