Mach Speed

Mach Speed (ブーストダッシュ, Būsuto Dasshu^?, lit. "Boost Dash") is a move used by Sonic the Hedgehog that, when activated, gives Sonic a short boost of speed. It has only appeared in Sonic the Hedgehog (2006) as one of Sonic's Custom Actions. It can only be used after Sonic obtains the Blue Gem.

Description

In order to use Mach Speed, Sonic has to possess the Blue Gem Level Up Item. Once obtained, the player has to select the Blue Gem with the directional pad and activate it by pressing down /.

When using this move, Sonic can perform a fast, but very brief "Boost-like" Dash visualized by sharp Blue gusts of wind that briefly trail behind Sonic that increases his speed to its maximum. If Sonic runs into an obstacle while dashing, he will fall down on the ground for a few seconds before getting up.

Trivia

• The mechanics of the Mach Speed are similar to the Super-Speed Stages sections found in certain action stages of Sonic the Hedgehog (2006), though Sonic does not lose any Rings when he collides with objects.
• When ramming into something with Mach Speed, a glitch will occur where blue winds will still appear around Sonic while he runs at very slow speed.
  • Additionally, although the description says that Sonic will damage most enemies in his path, this is not the case in-game, as colliding into an enemy will damage Sonic instead. It's most likely that this was a feature scrapped for time.
• In real-life, the term "Mach Speed" derives from the word "Mach Number" which is actually a ratio of a body moving at the speed of sound. 
• This move functions similarly to the Speed Up special attack in the multiplayer mode of Sonic Adventure 2.