Not the pepper, but the strange "marbling" effect on it. I thought maybe something nibbled on it, but it's like it's under the surface somehow! Two peppers look like this. A sign of some sort of deficiency, or is it some kind of bug? I cut it open and while you can see the marbled area in the skin, it doesn't look like it goes all the way to the inside of the pepper. I've gotten perfectly good peppers off this plant and none looked like this before. There are still quite a few on there that look perfectly fine, too. What's going on here?
