Wheel Gator
Alright, now the boss. You'll notice that there is no floor to this room. Instead, it is oil. Wheel Gator hides in this and occasionally pops out to try to snag you.
His first attack is signaled by the oil moving in waves. Jump up on the wall and keep on it. A spike wheel will emerge and circle the whole room. Avoid it and the oil settles. Be careful because this is when he will jump up to snag you. If he gets you, he'll bite you for three damage. If he doesn't, he'll stay out for a few seconds.
His second attack is when he jumps out and charges up the two wheels for his shoulders. He'll fire them above and unto the wall where they will circle up and back. Avoid the wheels and punish him for trying to get you.
His third attack is a spinning attack. He spins and dashes towards you. Jump over to avoid.
If you have the S. Chain, use it. That's his weakness.