A Mook is an alien species from the Mother series, who follow orders from the final boss Giygas. Mooks appear late in the game, normally serving as strong enemies. Much like other extraterrestrials and robots, they are absent from Mother 3.
Mooks look a lot like stereotypical extraterrestrials, featuring green skin colors (though this varies), three eyes, two of which are separated from what seems to be their head, and many tentacles. They are able to use PSI, possibly thanks to Giygas. In EarthBound, Mooks are notable for being able to diamondize a character with their glare, making them dangerous enemies.
List of Mooks
(+) Max HP: 85 - Max PP: 80 - Offense: 50 - Defense: 110 - Fight: 50 - Force: 30 - Speed: 40 - Strength: 30 - Wisdom: 100 - Exp.: 166 - Money: $42 - Item: None
Oh-Mooks are the more powerful versions of Mooks. These can also steal items from the characters.
(+) Max HP: 160 - Max PP: 250 - Offense: 60 - Defense: 140 - Fight: 10 - Force: 100 - Speed: 65 - Strength: 100 - Wisdom: 250 - Exp.: 175 - Money: $110 - Item: None
(+) Max HP: 610 - Max PP: 290 - Offense: 82 - Defense: 135 - Speed: 19 - Guts: 24 - Exp.: 24291 - Money: $1648 - No chance of getting an item
Lesser Mooks are the lowest rank of Mooks in EarthBound.
Mook Seniors are higher-ranked Mooks found in the Stonehenge Base.