Grim Creeper

The Grim Creeper is a cowardly mini-boss. Link encounters him midway through the Eagle's Tower dungeon of Link's Awakening. After a short introduction, Grim Creeper proceeds to use a flute to call six Big Keese to attack Link. To defeat them, Link must destroy the Keese before they leave the screen. If he misses any, he has to try again. Any weapon will do, but the sword is by far the easiest to use. Once all the Keese are destroyed in one blow, Grim Creeper flees, but not permanently. He comes back to ride Evil Eagle in the final boss battle in Eagle's Tower.

Trivia

 * Its name is an obvious reference to the Grim Reaper.
 * The flute the Grim Creeper uses may be a reference to the Flute from the original The Legend of Zelda. Judging by the creature's Japanese name, it is a piccolo.
 * The Skull Kids may have been inspired by the Grim Creeper, as they also play a flute that they use as a weapon or to summon monsters and also wear Skull Masks. Whether Grim Creeper is wearing a mask or not is unclear.
 * The battle with the Twilit Carrier Kargarok is similar to the battle with Evil Eagle and Grim Creeper, as both involve a masked rider commandeering a huge bird.