I've gone in the Hollowshade Moor entrance to Palludal several times. This mob starts off low level. Kill it, the next one is higher. It cycles through 3, then starts over.
My Ranger 16 killed one, it was light blue, the next one to show up was dark blue. The next one conned white. The next one, I don't remember for sure, was either green or light blue. I attacked more muck diggers then went back to this mob. It went through the same level cycle again.
Yes, they do move if you attack one. Otherwise they stay put.
Got a lens off one, and the fungus sleeves off another one, the edible mushrooms from another. The rest I got xp, but no drops.
If you go after all of the reishis and bugs just inside this palludal entrance, then med and get your hp back up, they are all back in place. Temperance is a good thing to have. Levitate saves from falling going back and forth between the Shar Val city and this entrance of Palludal.
Watch out for mobs in the Moor as you travel back and forth, unless you are high up on the wall.