Use charged Sonic Slicers to defeat them as they come from below and hit him. You are safe on the platform of his machine. It's hard to hit him head on but you can use normal Sonic Slicers too. Serges has been destroyed.

Who is weak to wheel Gator?

It is recommended to stay on the walls unless X is chased by the wheels as, if he stays in the liquid, Wheel Gator can grab him in his jaws and chomp him, causing serious damage. Gator's weakness is Strike Chain, which can really put a dent in his power.

Who is weak to Sonic slicer?

Sonic Slicer is the weakness for Blast Hornet, Sigma's two forms, and Storm Eagle.