Zap Comix No. 15
All good things must come to an end, the saying goes. And after 36 years, so does Zap, though Zap #15 does try to have no end, as it's a flip book and has two front covers and only a middle! And yes, the garish cover pictured above, by Paul Mavrides, is the official front cover, as it includes the publishing indicia on the inside, whereas the more traditional cover by Gilbert Shelton (linked on the right) does not.
So the "new kid" Mavrides not only gets his first Zap cover, he also gets the inside front cover (a series of iconic skull graphics) and the opening story, the two-page "Jesus Fucking Christ!"