In zangarmarsh, you can get a quest called "Balance must be perserved". The questgiver will give you a ironvein seeds so you can cast it and it will destroy the steam pump controls. (thottbot/alla the quest for more details pls). When you use it and destroyed the controls, a mob "Steam pump overseer" will spawn. You can repeat this all you want. You can loot it, but YOU CANNOT GET CENARION EXPEDITION REP AND EXP FROM IT. (I think blizzard already nerfed it.) For some reason i cant (or at some point i stopped) get(ing) any rep from any naga in the area too (I still get them from the slave dranei and im still friendly with CE). The cool thing about this exploit is, you the mob often drops the unidentified plants which you can turn in 10 for rep (250) and some random plants. (it will have a chance it will give you a undiscovered species which willgive you 500 rep more).
The mob drops 2-18 (~8's at average)silver, unindentified plants, level 58-62 TBC greens, clams (contains jabbal pearl and golden pearls sometimes) and edible fishes.
More info, mobs have 5600hp, and does ~200 DPS (according to my mod). The mob knockdowns sometimes. This mob is not a problem for my 300-400 dps 62 rogue. i eat the fish it drops every 6-10 kills, i got 5500hp too. Sometimes i can down one without getting hurt..