The Barrel Worm is by far the most physically imposing boss you've encountered so far. It has very high ATK, HIT%, and
DEF. Don't try to bang heads with this thing, 'cuz it's head is harder.
Like always, SAFE and BLINK for defense, put together with BLIND and CURSE and you should be invincible.
The worm's M.DEF isn't too high and he has no resistances, so if you've built up some instant-deaths spells,
go ahead and take it all the way. The only thing to worry about this battle is the big worm's physical attack,
so either wipe out his offense, or take him out quickly.