Biris are a recurring jellyfish-like enemy in The Legend of Zelda series that debuted in The Legend of Zelda: A Link to the Past. They are usually electric creatures who are the aftermath of a Bari spliting into smaller versions after being damaged.
The Legend of Zelda series
A Link to the Past
In The Legend of Zelda: A Link to the Past, they split from red Baris. They periodically make themselves electric, which means Link must wait for them to stop to attack or he will take damage from the shock. They can be defeated from afar with various projectiles without taking any risks.
Ocarina of Time
In The Legend of Zelda: Ocarina of Time, they are found inside Lord Jabu-Jabu. They can be found floating around by themselves or can be created by attacking a Bari. Attacking a Bari will cause it to split into three Biris. They can shock Link on contact so he needs to uses his Boomerang to deal with them. They can also be stunned with a Deku Nut, which allow them to be killed with melee weapons.
"If you touch it, you will be electrocuted!"
Oracle of Ages
In The Legend of Zelda: Oracle of Ages, they are pretty similar to their A Link to the Past incarnation and they behave the same. The major difference is their color, which is blue instead of red.
A Link Between Worlds
In The Legend of Zelda: A Link Between Worlds, they appear in three colors; red, yellow and purple. Each color split from their respective Bari. They will once again emit electricity to protect themselves from Link's attacks. They can be stunned by the Tornado Rod in order to attack them directly.
Cadence of Hyrule
In Cadence of Hyrule: Crypt of the NecroDancer feat. The Legend of Zelda, they are found in various caves and dungeons. They move to the beat of the music in a specific pattern, where they can only move diagonally in the shape of a diamond unless blocked by an object. They will electrify their body for the duration of four beats before loosing it for another four beats. They must be attacked when they are not electrified or Link, Princess Zelda, Cadence, and Yves will take damage.