Ninja Squid
From Inkipedia, the Splatoon wiki
With Ninja Squid, you leave no trace while swimming on horizontal surfaces and ramps. However, your swimming speed is a bit slower. This ability is restricted to clothing as a main ability.
In-Depth Ability
Use
Ninja Squid is used to move around a stage undetected. Because there are no ripples for enemies to spot while the player swims, the player can sneak to a better vantage point for attacking the other team, or can easily escape from an enemy's attack, such as the Kraken.
Gear
Ninja Squid is the main ability of: