(2B pencil on a 139mm x 87mm postcard)
One of the better products you were able to get from comic book ads was the Exploding Army Hand Grenade. It wasn't a full-sized one and was a bit crude looking (nothing like the picture) but it was pretty good in the way you could load caps into it. In this Wizbang! advert, I've spoofed that by having it as a pocket atom bomb that kids can have fun totally destroying their neighbourhoods with.