Yup, made a brief tweet about it, which elicited a few "icks" of sorts, so now shall post here. Anyway, was brushing dog and this dog has fur. I mean, he could be mistakened for a woolly mammoth (Sheltland Sheepdog). However, we found what grossly enough looked like a twisted toenail growing out of his *tail*. I mean, eeeeuuuuu. My brother said, oh, he broke off the other one a while ago so maybe it grew back, which seems to be the case. Anyway, after grumbling why couldn't he have grown this icky little horn thing out of his head as then it would be great for Halloween, I went off to the internet.
Today, I hit the jackpot. Sorta. It seems this is a cutaneous horn, which dogs get, cats get, etc. etc. and even people get 'em too. There are some rather er, um, fascinating photos on the web of people who have let big ones grow on them! Anyway, he'll probably have a vet visit soon so we'll deal with it then.