Detective Comics 478 (DC, 1978) 1st full appearance third Clayface!
Last 35-cent cover-price. Cover pencils by Marshall Rogers, inks by Terry Austin. "The Coming of... Clayface III!" script by Len Wein, pencils by Marshall Rogers, inks by Dick Giordano
Preston Payne uses blood from Matt Hagen, the second Clayface, to try to change the effects of hyperpituitarism on his appearance; But the "cure" causes Payne's flesh to melt like wax and forces him to periodically dissolve others into protoplasm. When Batman interferes with Payne's theft of the components necessary to reverse his condition, he may become Clayface's next victim.