Excalibur, Sword of Kings.

Equipped Creature get's +7/+7. and First strike.
Can only be equipped to a human creature with converted mana cost 4 or greater.
As long as this card is equipped to a creature with toughness 4 or greater
both this artifact and its creature have hexproof.
Equip {7} ({7}: (Attach to target creature you control.
Equip only as a sorcery.)