In Beasts' Domain: Known to spawn at /location -3160, 2130, -6 (southwestern part of the zone's middle section; one known PH is "a grendlaen pouncer").
PH is a grendlaen pouncer. There are 3 in the area, 1 roamer, 2 static. I've seen it spawn as the roamer, but other sites list it as being the static. In any case, the static is at -3167, +2134, -7 and you can see the others from that location. It's by the Jorth, Elder, Bopo locations.. pretty close .. east of them, but you can do 4 namer, rotation, if you're fast. Or jorth, elder and bonecracker, if you are slow or afk a lot, like me.
Edit
Can spawn from the roamer you can see from there. or the one farther north you see from that loc... or that loc .. had it spawn from all 3 tonight.
Found this on track early (6a.m. EST) this morning with just our group in zone, it was in the southwest corner of the middle section of the zone not far from the west wall.Group was 91 rng and ench, 2 level 92 mages and 2 tier 5 cleric mercenaries, all of us with the best HoT group gear. The DD/knockback was taking out half of my ~60k HP and almost wasted one of the mages in group. I never noticed a knockback but one of the mages got punted out of patch heal range (purpled but alive). Guessing the AE DD was hitting every 30+ seconds but it didn't affect me (ranger) as much as it hurt the mages and enchanter.
Patch heals were needed on the tanking mage pets, one of them died and I got summoned and had to hit weaponshield and jolt off aggro when 2nd pet went in. It was a straight dps marathon, no special tricks other than keep the tank alive. Naturally you'll want to clear a few roamers along the west wall before pulling the named which is in a small clearing to the east, very close.