In Super Smash Bros. Melee, the moonwalk is a backwards sliding motion that can occur in the initial dash animation. It was discovered by the smasher Mr.C, and named after Michael Jackson's signature dance move in which it is one of the most famous dance moves in the world. This technique was also restored in Project M.
Moonwalking is achieved by tilting the control stick backwards while dashing, but without passing through the neutral position. The only way to do this is to rotate the Stick below the neutral position (as going above results in a jump), but just barely below to get the most out of it (thus, a very tight angle, as opposed to rotating the stick completely downward in a circle). This should result in the user doing a sort of backwards slide, but in a state more similar to dashing than to wavedashing.
Every character in the game can moonwalk, though several, such as Fox's, Falco's, and Marth's, are different in that they have an extra step: start from a walk (specifically not a run) in the direction opposite the way the character faces during the slide.
 Use in competitive play
The moonwalk is a situational technique; more often than not, it simply is used for extra flash. For more practical purposes, it can be used to mix up movement and bait opponents, overall adding a considerable degree of unpredictability to a person's play style. It can also be used as an alternative to wavedashing for edgehogging. In the case of characters with longer moonwalks, it can be used to move backwards much more quickly. Another noteworthy use of moonwalking is that it can allow a character to slide backwards and grab, effectively extending their grab range backwards.
Due to having the longest and fastest moonwalk, Captain Falcon makes the most of this technique, able to use the fast backwards momentum from moonwalking to fly off the stage and intercept recovering opponents with an aerial. In some cases, this may be a better alternative to going offstage normally as the moonwalk will move Captain Falcon much farther offstage and will also allow Falcon to retain his double jump, allowing for safer recovery.
 Moonwalking distance
The moonwalk is most noticeable when used by Captain Falcon, though some other characters, like Link and Mewtwo, also have rather noticeable moonwalks. The following characters can moonwalk the "easy" way (not requiring the extra step), ranked by distance:
An interesting property of the moonwalk is that its length and speed are considerably increased when the user is wearing a Bunny Hood. For example, when Captain Falcon uses the moonwalk with a Bunny Hood, he will zoom in the opposite direction a length equivalent to over half of Final Destination. In fact, every character can moonwalk at least a bit with the Bunny Hood. In order from longest to shortest:
A video showing all characters moonwalking to the edge.