A few nice sting images I found:
Blue dragon-glaucus atlanticus
Image by Sylke Rohrlach
Also known as Sea Swallow, Blue Glaucus, Blue Sea Slug, Blue Ocean Slug and Lizard Nudibranch.
Washed ashore at Bronte Beach, Sydney, NSW.
Diet: Bluebottle (physalia physalis)
Speciality: Stores stinging nematocysts from the bluebottle within its own tissues, which is additional protection from predation
Discovered: 1777, Forster
Image by lander2006