Animation Magazine #2 Vol. 6 (1992)
I finally found a DIC ad featuring Swamp Thing. The ad promotes DIC’s line of animated tv series from the early 90s. Swamp Thing the animated series was part of DIC’s lineup so Swampy made the roster within the ad.

For crossover appearance fanatics, Swampy is depicted with Wayne Gretzky, Michael Jordan, Bo Jackson, New Kids, Hammer, Mario, Yoshi, Sonic, Evel Knievel, 3 Stooges, Inspector Gadget, Battle Toads, Toad Stool, Princess Peach and more!

Below is the cover of the magazine that the ad is featured in.