The Mad Monsters were commonly sold in boxes. But Kresge, a discount chain that later became K-mart, wanted something unique. Just for Kresge stores, Mego packaged its action figures on colorful blister cards. Compare these to the AHI Super Monsters made later that year.
All of these photos (except Wolfman) are courtesy of Robert Acquarulo. See more Mego action figures and other toys at his web site, MegoCentral.Com