Stuck at the start of t2

There is a quest called awakened at last and I try to google it and can only find info awaking skills, so I google the boss I’m having trouble with “giant worm” And again a million results cause there are several bosses called giant worm!

So what do I do there are barrels and I try throwing them at the thing it does noting i shoot it and it says something like invalid text. I don’t know I can’t read it it’s so small and moves so fast. I spent 30 min throwing barrels at the thing then gave up let it kill me and quit. I’m sooo frustrated you have no idea, I don’t know what to do, worse than that I can’t tell if the things I try work or not!

I gave up on the barrels entirely, and just beat the thing down with my skills. I’m an ilvl 900’ish Bard, btw. Have no idea what the barrels are for. There was some text that disappeared before I could read it. Stupid game.