Octopuses are amazing in fact, and ever so suited for the imagination!
Most octopuses can change their color, texture, and shape. They change colors to camouflage, perfectly matching the background, and to show emotion. Octopuses have no bones and can squeeze through small spaces. They are natural shape shifters. Some types mimic other species so realistically that people don’t realize it's really an octopus! The mimic octopus (Thaumoctopus mimicus) is famous for this ability. From the Living Wonders book (Time, 2008): the mimic octopus "is one of nature's greatest shape-shifters: it is able to assume the form and coloration of at least 15 other species, including crabs, stingrays, and jellyfish." Scientists thought the octopus was truly the animal it copied.
(If an octopus can choose to mimic so realistically, why not choose to make skin pictures using the natural octopus color cells? Especially to talk to a dragon...)
Octopuses have simple brain-like bunches of neurons in each arm to help control the many possible movements. Each arm can move and react without any command from the big brain in the octopus head. There are also hundreds of suckers along each octopus arm that act independently to feel, grab, and release. Imagine having 8 arms that can move in spirals! Human arms are so very limited!