Complete the game 100%. Super Crash is an alternate form of Crash. He's stronger, faster and looks an awful lot like Super Sonic.
World 1 Boss
In this world you will collect a mutant named Spike . He is useful once you have leveled him up. To level up Spike, use him either in every level you play or just in the star level you get. This is a bonus level where you can upgrade Spike or just get a new one once he dies. Make sure you have the Spike costume. It allows you to upgrade him faster. At a level 2 Spike you can face the Boss. The boss is actually a level 3 Spike. Make sure you have the magician suit. That suit will increase your mojo or strength. To defeat the Boss, tap the touch screen to get your mojo going with Spike. Scratch the boss a few times, then press R + Y to power hit him with a special move. After that he should be dead and you will get a gem.
World 2 Boss
You can keep Spike but he will not be as useful as EE-Lectric. He can shoot electricity in balls and spit it out in random firing. Make sure you collect the EE-Lectric costume. Level up your mutant then face the Boss. Fire electricity at him a few times. Target by holding X and using the D-pad to move it so that you can hit him. You can now press Y before he does. You can execute a special move by pressing R + X or Y to kill him.
World 3 Boss
The mutant you get here is not strong enough to kill this Boss. Go back to World 1 and get Spike. Upgrade him with the Spike costume worn. When Spike reaches level 3 he will be ten times stronger. You should now have unlocked a special move for your friends by holding R + B or A. This move will hurt the Boss here very well. Smack him a little more until you win.