Backward shell hyperspeed
Backwards Shell Hyperspeed is a method of attaining Hyperspeed whereby Mario rides on a shell on certain steep slopes to increase his backwards speed. This technique can be used multiple times in a row on one or more slopes to further increase Mario's speed.
While riding on a shell, move Mario to a steep slope. Angle Mario parallel to the slope and observe that Mario will begin moving backwards while gaining speed. Once the slope runs out, one can repeat this process on the same slope or a different slope to continually gain speed.