Blanket Octopus - Tremoctopus spp.
Blanket octopodes (or octopuses, not octopi!!) get their name from the appearance of the female when she is threatened. Unlike most octopuses that produce ink, when threatened the female blanket octopus unveils a net-like membrane between her arms, making her look as big as possible.
Blanket octopuses have extreme sexual dimorphism. The female can reach lengths of over two metres whereas the males are only a few mere centimetres.
Blanket octopuses also have the unusual characteristic of being immune to the stinging tentacles of the Portuguese man o’ war. However, they do not feed on this creature, instead the octopuses rip off their tentacles and use them for their own defences.