Doomknocker

Doomknockers are a type of armored enemy wielding a spiked club.

Zelda II: The Adventure of Link
In Zelda II: The Adventure of Link, Doomknockers are a heavily armored type of Gūma in most later palaces, starting with the Island Palace. Like normal Gūma, they move back and forth over a small area while facing Link and occasionally jumping. Unlike them, however, they wield maces that they throw in a rapid straight line forward, which after a substantial distance reverse direction, returning like a boomerang. Sometimes they may jump over a returning mace, causing it to continue in the other direction. Potentially due to their armor, they also have more health than a normal Gūma.

In the Japanese version of the Maze Island Palace, the final stretch before the boss chamber features a Doomknocker in a teal color, matching the palace's walls in that version. However, it still is the same coded object; the blue palette is often given the wall colors in rooms with falling blocks, which that particular room lacks, but other ones with its layout have them. This Doomknocker is removed in western releases.

Captain N: The Game Master
In Captain N: The Game Master, a Doomknocker appears in the Island Palace in the episode "Quest for the Potion of Power." Its armor is beige, its club is wooden, and both are seemingly covered in outward-facing screws.