Hello people, I've noticed that my cat (2 year old male domestic short hair) has a claw with a dark patch on the underside (left 'index finger'). I've seen it before but I thought it was just dirt/hair caught under there, but now I can see that's not it. Does anyone know what it could be? It doesn't smell and is quite dry, and he doesn't seem to notice it at all. It's just different from all his other claws. Also, there seems to be a slight protrusion at the point marked with an arrow in the second photo. Any thoughts? Could it be fungus? Any help would be much appreciated!