Hero Roller

The Hero Roller is a roller in Splatoon and Splatoon 2 that is exclusively used in single player modes.

Splatoon
The Hero Roller has a futuristic design with a black and lime green color scheme shared with all the Hero Weapons, and many blue lights that leave a small trail as Agent 3 moves. It functions to the Splat Roller, being able to fling a decent amount of ink and spread ink by rolling it on the ground. It cannot be upgraded with Power Eggs like the Hero Shot, and unlike the Hero Shot, it only comes with Splat Bombs. It is exclusively used by the player during the Inkling Boy amiibo challenges, and completing them all unlocks the Hero Roller Replica for purchase at Ammo Knights.

Splatoon 2
The Hero Roller has a new, sleeker design, similar to the Carbon Roller. It is now usable in Octo Canyon without the use of Amiibo and can be upgraded one level. Unlike the first game, they now come with switchable sub weapons of Splat Bombs, Curling Bombs and Autobombs, along with every other hero weapon. It is loaned by Sheldon during the level, Enter the Octohurler, and can be used in all other missions after beating the level. Completing all the missions in Octo Canyon with the Hero Roller unlocks the Hero Roller Replica for purchase at Ammo Knights.
 * At Level 1, the weapon has blue lights, like in Splatoon. It functions identically to the Carbon Roller.
 * At Level 2, the weapon has red lights. It has increased fling power and speed, and increased rolling power. The upgrade can be purchased at the Ammo Knights Enhancifier with 1,500 Power Eggs and three Sardinium.

Hero Roller Replica
The Hero Roller Replica is a reward in Splatoon and Splatoon 2 unlocked through various means. It is a roller-type main weapon and is visually identical to the Hero Roller. Despite its unique appearance, it is simply a reskin of the Splat Roller from that game, sharing the same stats and loadout, sub weapon and special weapon.

Trivia

 * Callie's main weapon is shown to be the Hero Roller' or its Replica, likely from her time in the role of Agent 1. This is shown in her artwork for the Go all out! vs. Focus on healing Splatfest.