Savewarp

Savewarping or World Box Change is a glitch that makes an autosave in the wrong chunk, allowing the creation of save files with normally impossible spawning points. There are three ways to set up a Savewarp:
 * Dying in a chunk directly connected to the one you last autosaved in (to avoid a load screen), all without activating checkpoints so you respawn at the world crate. Only works in the NTSC Xbox version.
 * Getting a checkpoint while Cortex (or something else) is on a world checkpoint. The properties of the normal checkpoint impacts where the respawn point will be in the chunk. Works in every version except NTSC 1.0.
 * Hitting a world checkpoint with Cortex (or something else) while Crash is in another chunk. Works in every version except NTSC 1.0.

The new spawning point can be at a checkpoint, a gem or some other spot. It's possible to hit a world checkpoint with Cortex without it being in range by abusing of Cortex's idle animations.

History
In 2014 Gpro found the NTSC Xbox-only glitch and BetaM made a video with some examples. In 2018 Bandicraft discovered the second kind of Savewarping. . They later made another video with other examples.

H Skip practice file
Get an autosave at the checkpoint after Tikimon in the  chunk.

Dimension Skip practice file
Get an autosave in the  chunk using Cortex's idle animation.