From the Super Mario Wiki

The title of this article is official, but it comes from a non-English source. If an official name from an English source is found, the article should be moved to its appropriate title.

First appearance Donkey Kong (Game Boy) (1994)
DKGB Skullmask.png

Gyātoru (ギャートル[1]) are enemies from the game Donkey Kong for the Game Boy. They only appear in the Tower in Stage 9-3. Just like Snipers, they walk around the environment in circles, walking up walls and on ceilings in the process. They kill Mario if he touches them.