I really liked the Migrus locker when looking for random loot to drop for my players.
I did change it up a bit.
I used a Pangolin body with the openers face.
walking around on two legs with a hunched back.
I also upped it's power.
Gave it familiar abilities that scaled with the bound PC.
The PCs of course didn't know what to make of it, and I kept control of it so they never saw it's stats.
BUT it had the parasite familiar Archetype. Which meant that occasionally while exploring, a random monster would come up and try to help... then it would inevitably die and the migrus would crawl out of it's spine like some backwards chestburster
