Black Excalibur Lancelot

Hexproof, first strike
Whenever Black Excalibur Lancelot attacks an opponent, gain control of target artifact that
player controls. If that artifact is an equipment,
you may attach it to Black Excalibur Lancelot and
it becomes legendary in addition to its other types.
Black Excalibur Lancelot gets +1/+1 for each permanent you control that you don't own.