For Hyperious there's a little column on the left when you first enter that you can hide behind to avoid his first blast. It's not perfect, but can be used effectively to defeat him if you spec out right.
Evolution shield is helpful too.
XBL GT: Ki11er Six (ones instead of L's and a space between the two words) Treasure Room glitch on Borderlands 2: http://www.youtube.com/watch?v=wuvwzTuUhqc
Moxxi weapons have healing properties, the rubi has the highest percent of them all.
Any level rubi will work, as long as you have it in your hand...just toss a telsa grenade soak up all that health. So with pete, as soon as you see him getting ready to do his AOE, switch to a rubi/moxxi weapon and run towards the sewer and wash off.
Hyperious has a pattern, and there are ways to avoid them legitly. I'd suggest going to the GBX forums for a better explanation on pretty much everything you want to know.
Ooohhhh that would've been very helpful too know, no one told me you could wash it off. I have the slow hand with the triple shot, fire. His shields are no problem he just eats me away.
They glow with a green color. Once you first drop you down, you can see the sewers(waterfalls), once you summon Pete, they stop flowing. Once youre corroded or on fire, hit the valve and get under the water fast and be carefuly, spiderants or a type of trash mob spawns along with the water, so tossing a telsa nade or something helps take them out with ease.