This is a blue ringed octopus. It is a small octopus that lives in shallow waters and tide pools along the coastal areas of the Indian Ocean and the Asian side of the Pacific Ocean.
This type of octopus is small (5-8 inches) and is as deadly as it is beautiful. I wouldn't want to meet one in person, dark alley or not.
Happy Octopus Day!
Image via Dan Koboldt