Slosher

The Slosher is a Main Weapon in Splatoon, made available in the 2.0.0 August Update. It was available from the start in Splatoon 2.

Splatoon
In Splatoon the Slosher is a bucket of ink that can be swung to splatter turf and enemies in a straight line. The trajectory of the ink can be adjusted to strike enemies behind walls. It's strong enough to splat opponents in only two shots, and comes in a set with the Burst Bomb and Inkstrike.

"A weapons-grade bucket that hurls ink straight ahead over an impressive range. By adjusting the angle, it can be used to hit opponents who are up high or even on the other side of a wall."

- In-Game Description

"This might look like an ordinary bucket, but it’s actually a weapons-grade bucket! Hurl ink straight ahead over an impressive range, and adjust your angles to hit opponents above you or behind walls. The Slosher comes with Burst Bombs and the special is a hot pastrami on rye! Er, wait. Sorry. I mean Inkstrike. Got a little excited about today’s lunch delivery."

- Live from the Squid Research Lab

Splatoon 2
In Splatoon 2 the returns with a new design that's primarily orange instead of pink. It is described as having redesigned handle and suspension.

Note

 * The Slosher deals more damage the farther away the ink travels, as opposed to Rollers and Shooters dealing less damage the farther the ink goes. In addition to this, more ink will be spread the farther away the ink travels, allowing for an easier time to hit targets. A close arched shot will deal 40 damage with no Defense Up or Attack Up perks, and a far arched shot will deal 70 damage. However, the Slosher will always deal 70 damage no matter the range if a direct shot is hit.

Demonstration
https://www.youtube.com/watch?v=NGDEz7IfcK8

Splatoon

 * The Slosher was first discovered in the June 24th datamine.
 * This weapon was later shown in a Japanese trailer detailing future Splatoon updates.

Splatoon 2

 * The weapon was first revealed to be returning in a tweet from the official Splatoon Twitter account on the 24th January 2017.