Canned weapons are a rare type of can with a main weapon or sub weapon inside that appear in the Octo Expansion.
In the Octo Expansion, some levels require the player to enter the stage unarmed but later have them gain weapons via canned weapons. These add the weapon to the player's arsenal for the rest of the mission.
Glooga Dualies, 
Splat Bomb
Blaster,
Slosher,
Octobrush,
Splattershot,
Splat Dualies,
Splat Charger,
Splat Roller,
Heavy Splatling,
Splat Brella
Octo Shot
Japanese
Dutch
