"The most powerful cannon around, it consumes a lot of energy."
―In-game text, Mega Man Maverick Hunter X

Fatboy (ファットボーイ Fattobōi) is a Shoulder-type cannon weapon that Vile obtains by defeating Boomerang Kuwanger in Mega Man Maverick Hunter X. When equipped with this weapon, Vile fires a large, pink and orange energy projectile from the cannon on his shoulder. Fatboy uses a good chunk of Weapon Energy, but it inflicts a decent amount of damage. Fatboy's range is at least a full screen's width.

Mega Man X takes a decent amount of damage from Fatboy.

Defeating Boomerang Kuwanger will Vile not only be rewarded with Fatboy, but he will also be rewarded with Metal Crescent as well.

Damage Data Chart

Damage values in units for Mega Man Maverick Hunter X.

MHX-Icon-Vile-Shoulder-Fatboy.png Fatboy
Boss Damage
Mega Man X 8
Chill Penguin 3
Spark Mandrill 3
Armored Armadillo 3
Launch Octopus 3
Boomerang Kuwanger 3
Sting Chameleon 3
Storm Eagle 3
Flame Mammoth 3
Bosspider 3
Rangda Bangda 3
Mega Man X 1*
Zero 1
  • Any damage value marked with a "*" means that the weapon will cause a weakness reaction for that boss.
    • In Mega Man X's case, in his second encounter in Sigma Palace, any damage entries marked with a "*" will break through his Rolling Shield.



  • Fatboy's name refers to the large size of the projectile. It is also possibly a reference to the Harley-Davidson motorcycle of the same title, which itself is named after the atom bombs "Fat Man" and "Little Boy" that were used on Japan in World War II.