You’re not seeing double. These 2 Swamp Thing sweatshirts have the same design. Around 1990/1991 they were available in various sizes and colors. I wrote about the size 10-12 sweatshirt from 1991 a couple weeks ago, here. 

As you can see, the turquoise background texture extends further than that of the sweatshirt released in ‘91.

This smaller sweatshirt is a kids/youth size 5/6. I’ve provided photos of the tag and manufacturing info, below.