This was a late 50's early 60's black and white. I remember the creature spent most of the movie in a cave. He had a beek for a nose, infact his facial expression looked somewhat like batman.
Occassionally small bat like creatures would fly out from under him and land on the backs of people.
The air was contaminated the the people remained in a home and the ground was desolate with somewhat of a low smoke affect move across it.

This is a tough one...anyone know????