The Monstrous Minnow (click for map image) has a chance to spawn after you complete the fifth step in the heroic adventure "Death Peace" (if the named doesn't spawn, a PH will).
Very irritating named. There's nothing particularly special about him other than wild rampage, it's just that he's in the water and hits hard and fast. If you have the option of pet tanking him, that would be much easier to deal with since fighting in water is awful.
Averaged 6480 per hit on a 9k ac, max tanking AA SK. Minimum Hit was 247 (bash). Maximum Hit was 17089. The damage from Wild Rampage was basically negligible being somewhat infrequent and only hitting 5524 on the high end. Over a very long (nearly 8 minute) fight, he parsed in at 9 million hitpoints.
Quick stats:
Min Hit - 247 Max Hit - 17089 (another post reports 18990) Avg Hit - 6480 Wild Ramp - 5524 HP - 9,000,000
Decided to fight it in the shallow nook at the north end of the lake. We wiped (at 1%), but the problem is the mob then got stuck in the west zone wall and it would not come out. I could hold aggro on it for 10 minutes and it would not leave the zone wall. So my advice is don't fight it there.
Just found this out the hard way myself. That shallow little ledge looked like a great spot to fight. Ended up the mob wound up behind the invis barrier, could no longer attack it. One by one it summoned group members until all were dead. Good times. Spent an hour trying to wiggle the thing loose, no luck. Wish I would have found this post beforehand :/
We too had the same smart idea and we too got the named permanently stuck there! Neither bard Highsun nor ranger flusterbolts nor agroing and waiting 10 mins to warp nor sending a mage pet and retreating shifted him. In the end we sent mage pet on him and the entire rest of the group simply healed pet and offered group AA clicks etc to help boost his DPS. A long time later, he killed the named and we were able to loot without problem.