How to create a claw out of this mesh? The mesh on the arms of my reptile are quite complex and I'm wondering what would be good way to make some appendages on this piece. I'd tried sculpting and proportional editing but was not able to make anything that resembles a claw. The mesh was generated using metaballs. 

Any tips or info on this procedure?
Beginning with a box primitive, I used vertex extrusions, then boolean modifiers to attach the claw to the arm (which will then be attached to the body).

Then I was able to sculpt this using smooth, crease, and clay strips brushes.