This monstrous octopus is a nightmarish sight - its eight long, writhing tentacles, beady eyes and gaping maw are a repulsive combination. The beast's skin is an oozy, sickly green shade, and its cresting tentacles look to be ready to pounce on unsuspecting prey. I would suggest using brighter colors such as blues, purples and yellows to contrast the octopus' green hue; use lighter shades of these colors to give depth to the beast's slimy skin. Dark shades of green and dark blue should be used for the tentacles and the eyes, which will help to give a feel of tension and terror to the picture. Finally, white or silver should be used to draw out the wrinkles and ridges in the octopus's skin, and yellows and oranges should be used to emphasize its gaping, toothy maw.