Shine spike
The shine spike is one of Fox's edge-guarding techniques. It consists of using Fox's down B to semi-spike an offstage opponent, in order to gimp them, preventing them from being able to recover. The shine spike is especially effective, because the shine has set knockback and hitstun, making it as capable at zero percent as it is at three hundred percent. Also, since the move slows Fox's vertical movement, it allows him to easily recover after spiking, especially in Melee, since the shine can be jump-cancelled in that game as well.
In Brawl, the technique loses some of its effectiveness, due to its variable knockback, but it still highly effective at stopping opponents with less than average recovery. Floaters, characters with two recovery techniques (such as Wario) and characters with a tether recovery are generally able to survive it at low damage percentages.
Shine edgehog
The Shine edgehog is a very useful tech for Fox offstage. It allows him to use his Reflector and grab the ledge after the move is done. First, the player must dash to the ledge. Before their momentum takes them off the edge of the stage, they must perform a Shine and quickly turn around in the air. (Note: This can be done without turning around, but turning around in the air gives more distance with the slide, plus Fox is then able to sweetspot the edge.) Doing it without turning around is practically useless, because it only goes so far, and players sweetspot the ledge before performing an unturned Shine.
This can be linked with a combo, like the waveshine. Characters with up special moves that meteor smash, including Ike and Kirby, can drag them down from the ledge, but if performed incorrectly, this tech allows a character to shine spike and edgehog.