After a long chase, you catch Croco in the Moleville Mines.
Battle Croco
Croco is tougher, but is still weak to Fire. When Croco's health is half full, Croco will say something, then he will crash into you, stealing all of your items. Because of this, you might not want to use Special attacks at all, because your only way to heal after you lose your items is to have Mallow cast HP Rain.
Croco has a regular attack where he charges into a character. You can block it by pressing the button as soon as Croco stops sliding backward after hitting the character.
He can also throw a small bomb at you. This attack can't be blocked.
After Croco steals your items, he starts using an attack called Chomp, where he throws a random enemy at you. You can block it by pressing the button as soon as the thrown enemy starts moving downward from the peak of its arc.
After the Battle
After the battle, Croco gives you back your items. You also get a Bomb, which you can now use to reach the second part of Moleville Mines.