You can keep Spike but EE-Lectric is much more useful since he can shoot electricity balls. Collect the EE-Lectric costume and level him up, then face the Boss. Fire electricity at him a few times while targeting (hold X and use the D-pad to move) so you can hit him. You can eventually press Y before he does. Execute a special move by pressing R+ X or Y to kill him.
Here you will collect Spike, a mutant that’s useful once you have leveled him up. To level him up, use him either in every level you play. Also, the star level 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, which allows you to upgrade him faster. You can face the Boss at a level 2 Spike. The boss is a level 3 Spike so make sure you have the magician suit, which increases your mojo or strength. To defeat the Boss, tap the touch screen to get your mojo going with Spike while scratching the boss a few times. Press R + Y to power hit him with a special move. You will get a gem after defeating him.
You will need Anubis-Vicious from stage 3. The boss has big combo attacks that do a lot of damage. First, give Crash the ninja outfit to outrun the freeze ray. Note: When he comes over, try to freeze him. Keep pressing Y to do the longest combo possible and take off a fifth of his health. He’ll use an orb to lift and hurt you. To avoid this, attack him while avoiding the orb. When at half health, he will make the drains cough up poisonous gases that hurt you. Avoid or freeze them. Keep attacking and avoiding damage and you’ll eventually beat him.
The mutant you get is too weak to kill this Boss. Go back to World 1 and get Spike, then upgrade him with the Spike costume worn. Spike is ten time stronger at level 3. You should have unlocked a special move for your friends by holding R + B or A. This move will hurt the Boss here significantly.