The Darkin Bow

Equipped creature has "{t}: This creature deals
damage equal to its power to target creature."
When the equipped creature dies, add a Soul
counter on The Darkin Bow.
If The Darkin Bow has 2 Soul counter on it, transform it.
Equip {2}{b} ({2}{b}:Attach to target creature you
control. Equip only as a sorcery.)