Sonic & All-Stars Racing Transformed

To earn this achievement that's called "Racing Transformed", you must go All-Star.

All-Star is a random item that you earn from one of the question mark boxes you come across during any idea. If you hear the announcer go "All-Star", that means that you have earned the item. To use it, press A, then A again and you will go "All-Star". I did this with Sonic after going through a couple of races, the third race finally netting me the All-Star item and using it during the race. The moment you go "All-Star", that's when the achievement should be unlocked.

Have fun and good luck!

This achievement can be earned in any track with power-ups on. To get this achievement, you will need to get the invincibility power-up: All-Star. This power-up tends to pop up more often if you are near last place in a race. Once obtained, simply press A to turn invincible, and the achievement will pop.