Conserve Ink—Splat Sustainably

 is the fourth mission of Happiness Research Lab.

Gameplay
This mission tasks the player with navigating a long obstacle course infested with a variety of Octarians, with a very limited supply of ink and no way to refill it. If they run out of ink, O.R.C.A. will splat them. At the end of the mission, the player is rewarded with 2 additional Power Egg packs and a unique compliment if they managed to navigate the level without using any ink (from the Captain) or splatted every enemy (from Agent 1). Reaching the end without splatting any enemies other than Octopods but used ink results in another unique compliment from the Captain, but no additional rewards are given.

Trivia

 * This mission's Octosniper has an aiming algorithm unique among the other Octosnipers: instead of simply following the player with the laser it's aiming, it goes slightly beyond in the direction where the stick is tilted, and therefore "predicts" the player's movement slightly. This behavior makes this Octosniper a tougher opponent if the player decides to pass by without using any ink against it.