This is the original cover painting created by Walter Velez (1939-2018) for the very first book in the well-known "Borribles" series of novels by Michael de Larrabeiti, in the edition published by Doubleday SF Book Club, 1979.  (I show the published book for reference)  Handpainted In acrylics on illustration board, 24" x 14" and is signed by Velez.