I have a halloween crab that killed my Blue Tuxedo Urchin. I got the Blue Tuxedo about a month ago and he always cruised the tank with no woories. Last night I found the Halloween crab over it but when I noticed it, all the spikes/hair from the urchin were removed, in other words, it looked bald. Has this happened to anyone else before? Did the urchin fall into a trap or did it just die and the crab was just feasting?