I am trying to kill Quadraxis what do I do?

At first - you'll notice that his feet are glowing. You need to go into Morph Ball mode and either Boost through the glowing areas or you could plant a Bomb so that it hits the glowing portions - but Boosting is easier better and safer.

When you've stopped all 4 of his feet from glowing - you�ll have to shoot his knees when they�re blue - when they get hit - they will flash red. Once you take out one leg - you'll have to repeat this process 3 more times for the other 3 legs!

You can dodge his missile attacks by jumping from side to side except for the one with the red lasers when he tries to lock on to you - I suggest going Morph Ball and Boosting away from it. If he goes into that top mode - where his legs go together - just lock on to him and fire a Super Missile.

Once his body breaks - his head will detach. Now - switch to the Echo Visor and target the antenna that�s coming out of the top of the damaged body. Then when that's down - target 1 of the 3 antennas on the floating head. Repeat this process for the other 2 antennas on the floating head. When all the antennas are down - his shielding will go away.

In this form - lock on and blast him with Super Missiles to stun him. Eventually he'll begin floating around in a circular pattern for a bit without attacking. While he's doing this - ride the Spider Ball tracks on the legs of the damaged body and then Boost yourself on top of the floating head when it's near you - the top of his head acts like a Spider Ball track so hold R. There are two Bomb Slots on his head. Nail both and he�ll finally die!!!

To further enhance Sheiny's Submission, I have a helpful suggestion.

Before you go and wipe out all 4 of Quadraxis's legs, try shooting 1 Super Missle at each kneecap first, because later, it becomes harder to hit its knees. At least when you shoot 1 Super Missle at each, you will only need 1 more to blast all of them.