Big Dark Stalfos
Big Dark Stalfos is a boss featured in Four Swords Adventures. They are incredibly large Stalfos who wield a green sword and have a ponytail. They were formerly the Knights of Hyrule, but they were transported to the Dark World and made into monsters by Ganon. Link must battle these monsters. Upon defeating them, he removes the curse placed on them and retrieves the Royal Jewels that they carry, which are required to enter the Tower of Winds. There are four of these bosses in total, and each will drop a different jewel.
The Big Dark Stalfos are trapped in the Dark World, and cannot be damaged unless Link uses a Moon Gate to follow them there. They fight very much like Chief Soldiers, except they are much larger and more difficult to defeat. Like Chief Soldiers, they carry a large shield and can only be damaged by attacks inflicted on the back or side. In battle, they also are accompanied by regular Stalfos, the amount of which increases every fight.