Babusu

The Babusu are shadow beings of the Dark World found solely in the Ice Palace of A Link to the Past. Babusu are completely black except for their eyes, which are a bright red. They live in dark icy cracks in the dungeon walls, and when they sense a intruder, they will swiftly dart from one hole straight to another at high speed. They are one of the fastest enemies in the game. Their eyes will glint in the darkness before they reveal themselves, but even knowing that they are coming might not be enough for Link to stop them, as they often appear in areas with moving or frozen floors. While virtually every attack, such as an accurate sword strike will destroy the creatures, they are able to cause considerable damage with their swift attacks until Link obtains the Blue Mail. The best method for dealing with them is to move slowly through the room and destroy them one by one.

Trivia

 * Babusu may be Japanese onomatopoeia consisting of "ba", meaning sudden movement or reveal, "bu" meaning to spit something nasty out, and "su" meaning a whoosh of something passing by, which accurately describes the behavior of these creatures.