You will encounter this Boss on the way to find a piece of the Vault Key.
Rakk will come off of it throughout the battle so be prepared to kill them or they will quickly drain both your shields and your health.
The Rakk Hive has 4 eyes (2 on each side of it's head) and shooting the eyes will give you critical hits. The eyes burst when a certain amount of damage is done to them. The craters left behind when the eyes burst is also a Critical Hit zone.
The Rakk Hive seems to only have 3 main attacks - the 'Acid Ball', 'Ground Stomp', and a Charging attack. The 'Acid Ball' attack is used on you most often when standing on the ledge above where the Rakk Hive is. The Rakk Hive spits out Acid Balls which, when they hit the ground, expand into an area effect of sorts with a cloud of acid above them, damaging you if you get too close to the spots (shooting from behind these will cause frame-rate issues). The 'Ground Stomp' attack is used when you get fairly close to the Rakk Hive. Finally, the Charge attack is used when you get close to the Rakk Hive and does a good amount of damage.
Snipers do not seem to work very well unless you play in Co-Op mode and one character pummels it with Combat Rifle or SMG damage while the other player takes out the eyes. Mordecai seems to work well against both the Rakk Hive and the Rakk as long as you've leveled up the Bloodwing's abilities.
(You will most likely encounter some frame-rate issues due to the size of the boss and the number of Rakk coming at you, especially if you use Combat Rifles or SMGs.)
NOTE: NOT my video, the credit goes to the original uploader of the video.