This is the Ugly Dog of Heaven. He made his first appearance in a minicomic I did with my brother, Glenn, back in 1989. Glenn wrote it, I drew it. That minicomic got reprinted in The Treasury of Mini Comics, volume 1. Most flatteringly, the publisher used a image of him on the spine of the book. 

Glenn later wrote him into segments of his thousand experiment on his Lovesettlement blog: each day for a thousand days he wrote a post of 100 words. If he didn’t finish a sentence one day he’d carry it on to the next. 100 words a day for a thousand days resulted in a 100,000 word stream of consciousness ramble. Is it a novel? An epic prose poem? An incantation to summon strange gods? Yes.