How often and when do these appear? Are they on a rotation or just random?
I believe there are two up at a time and they appear to switch weekly.
want more special signs
You have to do 3 normal world quests to unlock them typically , I haven’t seen one in the bug zone, but I also haven’t completed the chain.
Spiderland definitely had them, and one of the easiest at that. You fly around for 30 secs blowing guys up for no effort loot!