Bari

Bari are electric monsters found in Ocarina of Time Inside Jabu Jabu's Belly, or in the Gerudo Training Ground on Master Quest, and will electrocute Link on contact. They can only be defeated by using the Boomerang (or weapons such as the bow on Master Quest). Once defeated, it will split into a trio of Biri, which can also only be bested by the Boomerang.

In Twilight Princess, these guys are located in the Lakebed Temple. When you get close to them they start generating an electric field around them that only lasts for a while. When the shield is gone Clawshot the main part to take out their brain, looks nasty but it's the only way to kill them.