Grim Creeper

The Grim Creeper (ピッコロ使い, Piccolo User) 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 (ピッコロ [の子分]) to aid/hide behind. 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 Shadow Kargaroc Rider from Twilight Princess is slightly similar to the Grim Creeper, since both ride a vulture-like bird and are defeated in a similar manner. Also, the Shadow Kargaroc Rider wears a mask that is very similar to the Grim Creeper's face.