How do octopuses change colour and texture so quickly?

Octopus skin contains chromatophores, which are pigment cells that expand and contract to show different colours. They also have iridophores and leucophores that reflect and scatter light, adding shimmering or bright effects. Muscles in the skin can create bumps and ridges that imitate rocks, coral, or other textures. These rapid changes are controlled by the nervous system and can happen in less than a second. The ability is especially advanced in species like the common octopus and the mimic octopus.