I had spent 7 hours camping one spot for this guy (great thanks to Ezmode who offered this information http://forums.wow-petopia.com/viewtopic.php?f=3&t=7481), and the second I decided to go do some laundry he spawned!
Sure enough, he disappeared almost instantly and even though I had been expecting it, it still sent me into a state of mild panic. I circled the area once and after having completed a full round, found him again moving directly eastwards. I remembered to not bother trapping, and hit tame as quickly as I could. What did surprise me was that Nerfbat didn't seem to hit too hard. I began with 90k HP and finished with around 50-60k.
Anyways here's a screenshot (in Twilight Highlands - I quickly tried my luck with Sambas and Karoma, no such luck


Apologies for not taking one at the scene of the crime, I got a bit overexcited
