Found a method of farming this for crowns. Bring Zoologist, of course - and if you're in base game, find a HR 999. Chances are they'll have the ingredients and you can borrow them from that player. It is possible to get two Phantoms in one run. Keep in mind the time of day will change the look of this bug. Bring a Ghillie Mantle to avoid larger monsters. Start in the Ancient Forest from the Northeast Camp (11). Head to the Pukei-Pukei nest and before you pass the tree ramp, take the left path. Hug the right wall and crawl under some branches to meet a stream. It will be separate from the Cobalts. Don't see it? Head back where you came from and go to the Pukei-Pukei nest. Walk to the left side corner of the nest.

I think it is likely that they don't spawn in master rank ancient forest! I wasted like 20 vouchers for zoomaster and haven't seen one, then I tried in high rank and found it on my second try. Idk probably I was just very very unlucky.

I found mine at night but I didn't caught because I was too far away