Despawning and Respawning Glitch

Chip's Challenge 2 has some odd internal structuring that allows objects to be removed from a level through certain glitches and show up again on another level, or on the next playthrough of the same level. This behavior as a whole is known as the Despawning and Respawning Glitch.

Despawned state

Objects in a despawned state will be intangible and invisible to the level until they attempt to move. They will also persist across all level changes and resets while despawned.

Despawning objects

Via spring mining

All methods of spring mining can cause despawning if turtles are involved or if the tile being mined switches to an orientation that would not allow a block to be pushed on it.

Non-block entities, curiously, only despawn when spring mining a turtle, and not spring mining any other tile:

Note that dying and despawning, as it is defined, are different. If an entity that spring mines a turtle does not have flippers, they will simply die rather than despawn.

Via failed despawns

If you do something that should cause a despawn but the despawn is interrupted by a level change or reset, any entity that was on the tile where the despawn took place will be despawned on level load.

Entities will respawn as soon as they attempt to move, which is why the glider in the above gif had to be enclosed in toggle doors in order for the despawning not to be immediately undone.

Via swapping with a despawned object

If a despawned object respawn on a tile that already has an object on it, the despawned object "swaps places" with the present object, causing it to despawn.

Respawning objects

Despawned objects will spawn in the same spot they were before once the next level begins. They will only become tangible and visible once they attempt to move.

Objects can respawn on top of other objects. Suppose you were to reset an additional time after the glider-in-toggle-doors test:

Sometimes, upon a level change, despawned player entities will be unable to move and thus unable to respawn. Level resets seem to work fine.

key word SOMETIMES. i cant tell why that happens when it happens and why it doesn't happen when it doesn't happen

Because multiple despawned entities can have the same position, the above process can be repeated many times to spawn many players:

However, if there is not already more than one player to start with, the extra player will be unusable since player switching is not enabled in levels with only one player. (Also note that character switching is disabled once only one player needs to exit.)

Unsafe despawning

When NOT gates are introduced into a wired blue teleport system, they cause the resulting teleportation to be one-way. If the NOT gate leads to a wire that terminates without reaching a teleport, any object that enters the teleport will despawn. However, the game will then crash once you restart or load a new level and attempt to start the level, presumably because the despawned object now occupies an invalid position.

The gif above shows this happening with a player, but this crash will happen regardless of the object or objects that teleport.

If the currently selected player gets in this state, or you switch to a player that is in this state, moving will do nothing and you will be unable to drop/shuffle items or switch characters. Furthermore, teleports that have caused an unsafe despawn will act as though they are permanently partial posted, and will not allow anything to enter.