Ok, this thing is pretty highly spell resistant. I tried belly casting too and it didn't help. As a 72 necro, I was able to get tap dots to stick and my druid was able to get a swarm spell to stick as well.
At first tho, I just tried to pet tank it and the bugger kept resetting. So I went and stood under her belly and cast tap dots and melee'd. Went down finally, but was close because my merc was just about out of mana after she reset 5-6 times. Gotta keep a player aggro on her or she will reset, so might as well just run up to her spawn point ans camp her belly til she is dead.
Got the usual drops..
Ho Hum
Vorpil Atrocity
72 Blight Lord on Emarr