Okay, so, this nameless deer appears on the god hill, right? Then it laid down, and suddenly had Darcy's full set! Then it turned into a fawn (nothing unusual there). We followed this strange creature. It ran through the crying idol, and suddenly had the butterfly pelt again! Though now the antlers had disappeared, but the mask stayed.

I know stranger things have been seen, I have seen the screenshots. But this is the first time I've encountered anything like this.
I suspect the "nameless deer" was really the infamous Sluggs. Perhaps his pictogram just didn't show up for me, or else he did that on purpose.

It's just too bad I wasn't able to stick around to see if any other odd things happened.

(btw, anyone know who the fawn is in the first picture?)