Sparks are recurring enemies in the The Legend of Zelda series. They are usually represented as spherical enemies surrounded by a field of energy that hurt Link on contact. They are usually invincible but when they can be killed, their weakness is the Boomerang. Groups of Sparks are known as a Winder.
A Link to the Past
The Spark makes its first appearance as an enemy in The Legend of Zelda: A Link to the Past. In this game, they appear as balls of energy that can be red, blue or yellow. They are unkillable but since they can only move on walls, they can be trapped or restricted with jars or movable blocks.
In The Legend of Zelda: Link's Awakening, they appear as big electric balls with two eyes and a smiling mouth on it. In this game, they can be killed if sprinkled with Magic Powder, which turns them into a Fairy. A giant unmoving and undefeatable Spark appears in the Face Shrine however.
In both The Legend of Zelda: Oracle of Ages and The Legend of Zelda: Oracle of Seasons, they appear once again as a ball of electricity with a smiling mouth and two eyes on it. They are black and white this time around instead of their usual colored selves. They can be defeated with the Boomerang and releases Fairy as a result.
The Minish Cap
In The Legend of Zelda: The Minish Cap, their appearance is quite different as they appear as floating jellyfishs surrounded with an electric field. They still cling to walls and can once again be defeated by the Boomerang for a Fairy. It is the only game in which the Winder and the Spark appears as different enemy as the Winders of this game are a row of fireballs while in every other games it is just a group of this game's depiction of a Spark.
In The Legend of Zelda: Phantom Hourglass they only appears in groups and are completely invincible. They appear as three black balls surrounded by electric sparks that cling to walls.
A Link Between Worlds
Their is no Sparks in The Legend of Zelda: A Link Between Worlds but Winders can be found in a single room of the Dark Palace where one roams a dark lmaze populated by Red Kodongos. They are invincible and have the appearance of a row of five moving fireballs.