(CC-BY-SA 3.0; built on photograph by Seeeko, Wikipedia) It looks like a can-can dancer!
This one shows the stripeyness a bit better:
Based on photographs in PLOS ONE article: Caldwell RL, Ross R, Rodaniche A, Huffard CL (2015) Behavior and Body Patterns of the Larger Pacific Striped Octopus. PLoS ONE 10(8): e0134152. doi:10.1371/journal.pone.0134152; see all the figures and artwork!
The body language of animals makes for fascinating reading.