"The 1,001 Plas-sassins" from Plastic Man vol.2 #5 (DC, 1967) by Arnold Drake and Win Mortimer
Though Plastic Man was a DC character as of 1952, it wasn't until the late 60s that they finally used him! And not very well at that. I'm always disappointed at Win Mortimer's relatively stiff Plastic Man. It only lasted 10 issues, and the numbering was continued in a no more successful 10-issue series almost a year later.