Air Cannons are a type of enemy encountered within Bowser's body in Mario & Luigi: Bowser's Inside Story and its remake Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey. Here, they are only found within the Airway.
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Air Cannons are teal-colored creatures with a black star-shaped face, indicating that they have been affected by the Dark Star. Air Cannons carry around their own pink Bill Blaster, which has a set of wheels that it moves on.
Air Cannons attack by shooting their _targets, either firing straight Bullet Bills that may perform a small quick loop or fly straight ahead and can turn invisible. Alternatively, Air Cannons shoot from their spot on the battlefield, with the Bullet Bills flying in an arc. The second and third bullet Bills will vanish, but all three have to be smashed with a hammer strike in the same rhythm to absolve the _target of damage.