It is a threat. It is mostly made out of green smoke, everyone who looks at the smoke can make out a face, which appears to be a green blobfish, facing towards them at all times, no matter what.

It always moves at a slow speed of ██ miles per 2 hours. It never stops moving, and it makes no footsteps. it has a field, which breaks any lights in a  █ by █ meter radius. It exhales a smoke that induces cleithrophobia. 

It is partially blind so it uses echolocation. Its scream sound like chains.