Winder

Winders, also known as Moldola, are moving row of fireball traps appearing in several Zelda games. These beings cannot usually be defeated. They usually look like several Sparks strung together.

Characteristics and Variations
Winders originally debuted in A Link to the Past. They are made of fire and appear very similar to Sparks and Spinning Bars, and first appear in the Swamp Palace, but are common in many Dark World dungeons. Unlike Sparks, their movement is slightly unpredictable, changing direction randomly whenever they hit an object. They also appear in Four Swords and The Minish Cap acting the same way, although in these games they can set fire to Link, making them very dangerous when combined with other enemies or traps. In The Minish Cap, they can be found in the Temple of Droplets, the Palace of Winds, and Dark Hyrule Castle.

In both Phantom Hourglass and Spirit Tracks, these monsters are now electrically charged and travel solely along walls, and so much as touching one will shock and hurt Link. In Spirit Tracks, they're now named Moldola and are actually helpful against Heatoise, as it is weak against electricity.

Strategy
They are invincible in most games, so it is best to avoid them entirely. However, in Spirit Tracks, they can be defeated by firing an arrow at the "head" of the being (the largest ball of energy).

Trivia
Their appearance in A Link to the Past, Four Swords, and The Minish Cap is somewhat similar to the Moldorm from The Legend of Zelda. The similarity between the names, Moldorm and Moldola, should also be noted.