Taking note of Jin Saotome's version, I decided to create my own 'Slash', the black-eye mask wearing snapping turtle.
I added sculpted nails using Kneedite/Citadel 'green stuff'. However, since the plastic this figure is made from is slightly waxy (in the same way GI Joe/Starwars joints are) - sculpt doesn't bond to it well. To get around this, I sculpted on the figure, let the material cute, the 'popped' each nail off the figure, used some airplane-grade superglue, and reaffixed it.
I'm working on one for myself, and another to sell on eBay, since Slash seems to be a popular character.
So, using some google-image photoreferences, I sculpted an accurate snapping turtles shell for this figure.