Blizzeta

Twilit Ice Mass: Blizzeta is the boss of Snowpeak Ruins, the fifth dungeon of Twilight Princess. The boss is actually Yeta, a Yeti that leads Link to the second shard of the Twilight Mirror which she holds. She becomes possessed by the Mirror Shard and screams at Link that he cannot have it. The windows of the bedroom shatter, and snow and ice pour in, surrounding and encapsulating Yeta. The Ball and Chain is the only effective weapon throughout the boss battle. After the confrontation, Yeta's husband Yeto appears and comically knocks Link out of the way (apparently not even noticing him) and romantically embraces Yeta, and in a humorous (although touching) moment sends out many small collectible hearts and a Heart Container. For some reason, after a few hits with the Ball and Chain, the ice starts to take a shape not unlike that of a giant Mini Freezard.

Strategy
Blizzeta's first form is reminiscent of an enormous Babushka/Matryoshka doll. She spins around the chamber, and the Ball and Chain must be used to chip away at the layers surrounding her until barely anything is left. Afterwards, she encases herself within another ice barrier and rises into the air, summoning huge ice spikes around her, which will hover over Link and attempt to impale him. After they fall, Link can break them with his Ball and Chain, and tries to vanquish as many as possible while they're down, as afterwards they proceed to rise and form a circle around Link to trap him, so Blizzeta herself can attack. When she falls, Link can swing away at her just like the other spikes. By doing this three times, she is finally defeated.

Trivia

 * The ice pillars that surround Blizzeta when she is hovering in the air resemble the Snowhead Temple from Majora's Mask.
 * Since the only weapon that can be used on Blizzeta to cause any damage is the Ball and Chain, this boss does not experience a Critical Point, or a narrow space of time where Link is able to strike at a boss in fatigue, or other state, denoted by a triumphant music change.
 * When the ice masses surrounding Blizzeta are hovering in the air, they sometimes drop Recovery Hearts. These recovery hearts, along with those released by Yeto and Yeta when they embrace, are the only recovery hearts in the entire dungeon.
 * Blizzeta is one of the few bosses in Twilight Princess where an eye isn't its weak point.
 * The way Blizzeta turns her head all the way around and takes on a more frightening appearance after becoming possessed may be a reference to the Linda Blair movie The Exorcist (especially since Blair's character in the movie turns her head all the way around as well).
 * The line "NOT TAKE MIRROR!" has become a popular internet meme.