The yo-yo glitch refers to a glitch done using Ness's yo-yo. It can be used to attack or grab with near limitless range or attach certain single-hitbox attacks to Ness's body. The discovery of the glitch was a collaborative effort between VilNess, LonelyNess, and Dan Smith, and was spurred on by an innocuous video of an unknown Japanese player accidentally dropping a yo-yo hitbox.
In Melee, the glitch can be performed in all versions of the game.
Ness's up smash consists of 3 parts each with its own hitbox: outreaching, spinning, and swinging. The yo-yo glitch drops the last hitbox of the up smash onto the ground and leaves it there until Ness gets KO'd or uses a non-projectile attack.
How to perform it
After using the yoyo glitch, certain other attacks can be used to replace the yoyo hitbox with the hitbox of the attack used. The rules of the regular yo-yo glitch still apply when using a jacket.
If any non-projectile attack other than the ones listed is used to hit all targets between Ness and the location this glitch was performed, the jacket will be transferred to the opponent, allowing for near-limitless range.
Super Yo-yo Glitch
It is a very rare occurrence, so very little about it is known. Its effects (including but not limited to infinite Jackets and instant KO throws) are similar to those of the Yoyo Glitch, but are more lethal and have longer lasting effects.
This technique holds much value to Ness players and is said to be the secret to beating the Bowser Challenge.