The Octo-Ink (オクトパストラップ,Okutopasutorappu?, lit. "Octopus Trap") is an Action Item that appears in Sonic Free Riders. It is used to obscure opponents' views.
The Octo-Ink takes the appearance of a small and spherical pink robot octopus (akin to the Octus) with a red button on top of its head.
The Octo-Ink can be obtained from the different Item Boxes on the race tracks. When utilizing it, the Octo-Ink releases a squirt of black ink behind the character which becomes a black dome on the ground. If the racers make contact with the ink, their field of vision will be obscured for a short time, making it more difficult for them to race; in the player's case, this effect will obstruct the screen with black ink. While the ink will eventually disappear, the player can use hand-wiping motions to wipe most of the ink away.
To use the Octo-Ink in gameplay, the player must bring one of their hands up in the air and bring it down.