Fish Clip

Fish Clip is a trick in the Seaside Kingdom that is used in numerous speedrun categories. This glitch was discovered by Syrkl and involves abusing the physics of the ocean boundary with a Cheep Cheep to clip out of bounds.

This trick is often recommended even to beginner speedrunners, since it is relatively simple to perform.

Explanation

The boundary surrounding the Seaside Kingdom acts as more of a force field than a barrier, slowly pushing the player backwards when they get near it. The farther out the player gets, the stronger the force will be pushing the player back inward.

However, if a Cheep Cheep is uncaptured and left at the location of the boundary, it will not be pushed. This means the player can leave a Cheep Cheep near the boundary, and then swim away as Mario to cause the force to subside. Capturing the Cheep Cheep with Cappy will cause Mario to warp back to it, leaving a temporary window where the force from the boundary has not yet caught up with the player's position, and the player can swim further out than normal.

Execution

The location where Fish Clip is performed

To perform Fish Clip:

Capture a Cheep Cheep and bring it near the small notch in the ground by the kingdom boundary just east of the Bubblaine Northern Reaches moon (pictured at right).
Swim straight at the notch at high speed (achieved by pressing A/B and X/Y simultaneously to boost as the Cheep Cheep), moving roughly perpendicular to the boundary.
Just as the Cheep Cheep stalls and is about to be pushed backward by the boundary, uncapture it and swim away from the boundary as Mario. While being pushed away by the boundary, throw Cappy near the Cheep Cheep.
Once Mario has fully cleared the boundary's pushing zone, home Cappy in to recapture the Cheep Cheep.
After recapturing the Cheep Cheep, immediately perform a boost as the Cheep Cheep and then swim downward.

If the steps were executed correctly, the Cheep Cheep should clip out of bounds below the ocean floor.

Speedrun usage

Any%

In the Any% category, Fish Clip is performed just after collecting the Bubblaine Northern Reaches moon. After performing the clip, the Gap in the Ocean Trench moon is collected from out of bounds by shaking the controller to perform a spin attack. The loading zone to the Sphynx's Underwater Vault can then be entered from out of bounds, allowing the moon inside to be collected. The moon from the vault replaces the Taking Notes: Ocean Surface Dash moon from the previous route, which optimally utilized a Rocket Flower refresh to retain the Rocket Flower after collecting the moon.