Well, my idea is to use a cricket.
Seeming that Crickets are naturally black (here in the midwest at least) and they only come out at night, why not a stealth-driven class? How about a spy/ninja class. And they could use their tines on the back of their legs to help scale walls as well as use them to make an eerie noise right before he strikes!
Here are my images at the moment. It's not unwrapped or anything and right now he's at 421 polies/ 842 triangles.
Top:
Side:
Front:
Three-Quarter:
