Sand Storm	Its most common attack is a big blast of sand that it trails back and forth across the arena: You can easily avoid this once you notice him rearing back to breath, simply run to either the far left or right side of the room to avoid it.
Bubble Blast	Its second attack has the same telltale sign as the first, but he does it far less often. He'll rear back and release a big glob in the direction of where you last stood which slows down anyone it hits: As before, simply move to the side once you see him rear back.
Counter Smash	For those who like to charge in and press the attack, the Cave Worm will pivot back and forth making rocks fall and causing small radius damage: This one is hard to avoid when you're in mid-attack combo, but its best to hit him twice and back off expecting he'll do this attack. Or you can simply not get close to him thus not provoking him from doing it at all.
Suction	Not really an attack, but he has an ability should you stray too far away from him to suck you in closer to his position: It deals no damage whatsoever, so charge at him and let loose on his grotesque body; he won't attack you while he's sucking in.
Body Slam	When the worm gets low on health and you make a dumb decision to try and charge it, he'll raise his whole upper body and slam it to the ground for big radius damage: Simply put, don't get near him when he's that low on health. Stay back and attack with Holy spells.

Later Cycles: This battle is the exact same in the later two cycles with one major difference: The Cave Worms' increased stats. He'll be stronger, faster and harder to beat. Furthermore, his Electric Jellyfish friends will be a major nuisance during these later cycles. Its best to assign your chalice to the Wind element so you can resist shock and gun for the monster cohorts first before pressing the attack on the Cave Worm; because its not fun swiping at the worm and getting blind-sided by a jellyfish.