Here's a custom Battle Back that I put together. The default battle back 1 "Poison Swamp" was used as a basis, which I changed the hue of the water to resemble something more in line with what I had in mind. On top of that I created the waterfall image, with fallen tree and a few shrubs/shrooms/cattails. Use this however you like, just give me a shout out in your game's credits with a link to my profile on this site.
This is a perfect battle back for my Frogman enemy.