A slime concept art, I did for my upcoming game SauerCraft.
The archiv includes the original 512x512 big slime, and several variations in 128x128.
There are game ready 32x32 slimes for a RPG or Sidescroller, too.
I included the xcf for GIMP users.
I cutted out some arms from this concept art: http://opengameart.org/content/abomination-concept-art