The Shy Ghost Fish is an enemy that can be encountered in Old Madryn in Momodora III.
They function similar to the Boo Hoo enemy from Super Mario: If you look in its direction, it will stay still, but if you turn away, they will turn aggresive and move towards you. They deal damage on contact.
The Summon Stone ghost can kill these enemies will you look away. Also, with the right timing, you can kill them with paper seals by looking away when the seal reaches them.