Ball and Chain Trooper

The Ball and Chain Trooper is (as it's name suggests) a fully armored knight weilding a massive spiked ball on a chain. They appear as some of the hardest foes in several Zelda games.

A Link to the Past
The Ball and Chain Trooper, also known as the Mace Knight is a possessed Hyrule knight from The Legend of Zelda: A Link to the Past that wields a heavy mace, and first appears as the guardian of Princess Zelda's cell. At this early stage of the game it is the most difficult enemy Link has yet faced; the weapon it is named for has a long reach and does serious damage. It also recovers fairly quickly from being stunned by the boomerang. Mace Knights are the highest class of Hyrule knights and therefore are the most powerful. They require many swipes with the sword to defeat them. Bombs are also useful. When in doubt, the player should use the Boomerang to stop them in their tracks. Later in the game, when ascending the Castle Tower, Link must face several more of these foes.

Link's Awakening
In a Ball and Chain Trooper is encountered within Kanalet Castle, guarding one of the Five Golden Leaves you need to collect for King Richard. Other than this, Ball and Chain Troopers are rarely found in this game.

Minish Cap
These soldiers swing a damaging ball and chain, and are one of the hardest enemies in the game, but can be destroyed by:
 * 1) Dodging their ball and chains, then striking with your sword; or
 * 2) Using the Roc's Cape to jump over their ball and chain and perform a down thrust.

Quote from The Legend of Zelda: The Minish Cap Ball & Chain Soldier figurine: "Appears in the Palace of Winds and Dark Hyrule Castle. They're not fast, but that iron ball is a bruiser! Try to hit them after they swing the ball."

Twilight Princess
An enemy similar to the Ball and Chain Trooper also appears as the mini-boss of the Snowpeak Ruins in Twilight Princess. Named Darkhammer, he seems to be reptillian and to kill him you will have to Clawshot over him when he throws his weapon at you so you can hit his tail. Or you could sidestep to avoid his attack and use a Back Slice to get behind him. Vanquishing him will result in Link obtaining the ball and chain.