Clifford Simak 
Hellhound of the Cosmos 

The paper had gone to press, graphically describing the latest of the many horrible events which had been enacted upon the Earth in the last six months. The headlines screamed that Six Corners, a little hamlet in Pennsylvania, had been wiped out by the Horror. Another front-page story told of a Terror in the Amazon Valley which had sent the natives down the river in babbling fear. Other stories told of deaths here and there, all attributable to the "Black Horror, " as it was called.