Skip sandwich glitch

Ness out of bounds from using the glitch

The Skip sandwhich glitch is a glitch in EarthBound where it is possible for the player to clip through certian parts of a cliff while under the effects of a Skip sandwich, and skip parts of the game. In speedruns, this glitch is commonly used to skip the entirety pf Twoson giving the glitch its alternative name, the Twoson skip glitch.

Cause

Blue tiles are passable and red tiles are impassable

EarthBound's maps are divided into tiles. The game's programming designates each tile as either passable or impassable, with all cliffs being impassible. Because of the jagged shape of cliffs, they sometimes form 1-tile wide "nooks" where 3 of the 4 adjacent tiles are impassible. If this nook is diagonally adjacent to a passable tile on the other side of the cliff, it's possible for Ness to squeeze into this nook, and then cross over into the diagonal tile.

Executing the glitch

A cliff cannot be crossed by walking diagonally alone; it requires a combination of horizontal and vertical movements. It is best performed when under the effects of the Skip sandwich. The best way is to move in various directions, such as right, left, and down to squeeze through the nook. Failure can occur if you walk too far to the left before turning down because this can cause Ness to get pushed out of the nook or off the cliff. The nook itself can be entered with diagonal movement, but it requires precise positioning.

Uses

The Skip sandwich glitch is a simple way of being able to go out of bounds. The glitch is commonly used by speedrunners to skip early segments of the game, most notably Twoson. It can also be used to go out of bounds in Onett to access a specific corner to perform the Check area glitch.

Skipping Twoson

One of the most well-known uses of the Skip sandwich glitch is skipping Twoson. The set of cliffs south of the bus station can be crossed to access a road segment that connects Threed and Dusty Dunes Desert (see the game map for reference). From here, entering the haunted tunnel leading to Threed will cause the ghosts to carry Ness into Threed because this tunnel is normally intended to block progress into Dusty Dunes Desert until Master Belch is defeated. While skipping Twoson also skips rescuing Paula in Happy Happy Village, the game adds Paula to your party when Jeff reaches Threed.

Check Area Glitch in Onett

This glitch can also be used to access the northeast corner in Onett where the player can preform the check area glitch. This is one example of the benefits of using this glitch as opposed to the walk through walls glitch as the player can still check the corner to preform the glitch.