Hello,
This is a remix from https://opengameart.org/content/fire-slime by Spring Spring.

I am working on a CC0 asset pack for PlataGO! (but once it will be done, the sprite can be used elsewhere of course!):

I used the Dawnbringer 32 Palette, aligned all the sprite on a game ready atlas, and made some color variations.

I've mixed up 8 slime colors with 4 fire colors and I kept the original 3 frames animation
There is a spritesheet with a black background, and another one with a transparent background.

Attribution is not necessary as it's CC0, but if you do, you can use the following:
Fire Slime Monster Variations DB32, remixed by ImogiaGames.