Scientific name: Octopus cyanea
Taxonomy: Kingdom Animalia → Phylum Mollusca → Class Cephalopoda → Subclass Coleoidea → Superorder Octopodiformes → Order Octopoda → Suborder Incirrata → Superfamily Octopodoidea → Family Octopodidae → Genus Octopus
Locations: Hawaii, Indo-Pacific
Group: Marine Life → Invertebrates → Octopuses
The day octopus is, unsurprisingly, more active during the day. Note the manybar goatfish in some pictures; they often hang around octopus, and are a good way to find them before you're so close the octopus hides under a rock.
At night they hide in their burrows, and block themselves in with rocks.
When they feel threatened, they can release a cloud of ink. Please don't squeeze the octopus; the octopus needs that ink to defend from real predators.
They can change color and texture very quickly. These shots were taken just a few seconds apart:
As were these: