Allow a goliath to level up four times before killing him

For this achievement you need to kill a GOD-liath (Fatal GOD-Goliath). For a Goliath to become GOD-liath you'll need to get him to level up four times. You'll know when he's levelled up as he'll do a small animation, gain some health back and his name will change from Goliath to Raging Goliath, Badass Goliath, Super Badass Goliath then Ultimate Badass Goliath and finally GOD-liath. The earliest i could find one were in the Frostburn Canyon during the quest "Hunting The Firehawk". You have to shoot his mask off, he'll then go on a rampage killing everything around him. The ememies will actually start shooting him and he dies quickly so what i did when i saw one i killed all the powerfull enemies leaving few weak ones shoot his mask of and let him take care of the rest (you could also simply weaken the tougher enemies instead of killing them and then shoot his mask off), now if he's not level 5 by then there are plenty of Spiderants around Frostburn Canyon and since he'll follow you it shouldn't be a problem getting him to one of the spawn points. Its best not to shoot him at all, you want him to have as much health as possible, since they aren't that hard to kill. Now once he kills enough enemies he'll become a GOD-liath now you should kill all the Spiderants and take care of the beast. The achievement should pop right after you killed him.