An urchin covered in what look like small flowers, which are the venom apparatus rather than the spines.
An urchin to about 15 cm across, its surface covered in what look like small white and pink flowers on short stalks, with the short blunt spines almost hidden between them. It usually carries pieces of shell, rubble and weed on top of itself. Nothing else in the region looks like it.
The flowers are pedicellariae — stalked pincers, each a three-jawed grip with a venom gland behind it — and they are the danger rather than the spines. They seize skin on contact, detach from the animal, and go on injecting; the venom causes severe pain, and respiratory difficulty and muscular paralysis have been reported. Detached pedicellariae have to be removed. It is a photogenic animal and a completely hands-off one, and a gloved hand is not reliable protection against a grip that can hold onto fabric.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.