The mothmen in point pleasant when people were reporting was the brown acid flowing? The ironic thing is many of the reports the creatures seem to be what the book of lies refers as angels.
I've often wondered the same about the Cornish Owlman - which was first seen by a group of teenagers one night in, iirc, the late 1970s. Thinking back to my own teenage years, it seems very possible that the teenagers' judgement may have been a little clouded by some substance or other, and what they saw was in fact just an owl.