This is old news, but fascinating nonetheless. The octopus pictured below has 88 additional tentacles, a rarity, even for a creature as strange as the octopus.
This strange specimen is on permanent display at the Shima Marineland Aquarium in Japan. The octopus actually has 8 arms attached to its body, and the additional 84 tentacles are all extensions of those 8.
The 96-tentacled Common Octopus (Octopus vulgaris) was captured in 1998 in nearby Matoya Bay. It weighed 3.3 kilograms (about 7 lbs) and measured 90 centimeters (3 ft) long. Before dying 5 months after being placed in captivity, the creature laid eggs, making it the first known extra-tentacled octopus to do so in captivity. All the baby octopuses hatched with the normal number of tentacles, but unfortunately they only survived a month.
Currently there is no theory that fully explains the surplus tentacles, although speculation maintains the oddity to be the result of abnormal regeneration that occurred after the octopus suffered some sort of injury.