I wasn't going to write about this because it seems like such a pointless glitch, but after some thought it could be very useful in most runs, especially the VIP series.
For lack of a better name, the "Yoshi Despawn" item swap refers to a sprite taking the same #id as Yoshi as he dies. This will cause the item to "move" to Mario's position (or in some circumstances, 'nullify' the sprite, e.g. Goal Point or Springboard). Yoshi will then appear again under Mario if he goes through a pipe, door or exits the level (via goal, start+select etc).
Potential uses:
• Depending on the type of item you swap him with, Yoshi will either be Blue, Yellow or Silver. Thus, a Yoshi of a desired colour can be achieved based on the pallete of the sprite being swapped (it seems).
• Maintain flight without requiring Yoshi. If you can swap him before flight (or during ascension) then flight speed can be achieved without dismounting Yoshi.
• Taking Yoshi through doors, and also pipes that would otherwise be impossible (e.g. screen scrolling pipe).
• Taking items that came out of a block through a pipe whereby you need to keep Yoshi. (Second division sprites, or sprites with an #id higher than Yoshi, cannot be held on him).
• Bringing an item towards Mario. For example, flying question blocks can be moved so they will contain a different item.
It doesn't seem to work on 'standard' sprites, e.g. Koopas or Goombas, but it will with seemingly any Tileset-Specific sprite.
Here is a
sample (SMV). I haven't done enough research to know if this will be useful in SMW 96-exit, SDW, etc.
