Both of the move's official English names are a reference to the way the Mii's sword penetrates the ground upon impact, briefly holding the weapon in an unusable position.
When used, the Swordfighter slashes upward, knocking any enemy hit up while they also rise. Then, he/she holds the sword with the blade pointed down, and descends, meteor smashing enemies on the way down. The blade can pass through thin platforms, ambushing anyone underneath the platform the Swordfighter lands on. The Swordfighter is intangible during the initial frames of the attack. This move is very similar to Kirby's Final Cutter.
The meteor smash can be used as a sacrificial KO if the opponent cannot recover from the attack, but is unlikely to send opponents towards the bottom blast zone quicker than Mii Swordfighter would reach the same place itself until higher percentages. For this reason, Mii Swordfighter should attempt to grab the ledge when possible after hitting an opponent, if the move is to be used for KO purposes.
During the transition to Ultimate, the move was heavily buffed. It now travels higher and the player can move the Swordfighter slightly to the left or right during the ascent, thus making it more useful for recovery. The move can also sweetspot ledges from behind and boasts a larger hitbox. However, while its final hit has been strengthened in terms of damage output, its initial hit now deals less damage.
Special Move customization was added in Super Smash Bros. 4. These are the variations: