I had a hard time with this one till I read a strategy here for it... my water pet wasn't 25, so it made it hard... so I searched for a different pet with "water" skills and used the Electrified Razortooth on Twilight... which went really well!!! I popped the lightning sheild, rip, then used blood in the water and it instantly died! No moar lazer beam for that critter!

Amythel I used my Spawn of Onyxia, casting Deep Breath and Breath till it went down, and used a heal before the next pet came out...

The arise forth came the battle of Mini Thor against Helios... that damn spider stood zero chance against a Sticky Grenade in waiting right before Toxic Smoke and a couple Missles to its spider face!! Good luck!