I just discovered the remarkable picture archive belonging to the Réunion des Musées Nationaux. I (unsurprisingly) searched the term "mollusca", and the following are a few of the images of the incredibly charismatic (but shy) Argonaut Octopus I found.
The above painting is of the female Argonaut Octopus. Painted in 1839 by one Mrs. Jeannette Power.
The above is by an unknown artist from the 1551 book, "L'Histoire naturelle des estranges poissons marins"
I feel as if I'm in danger of falling into an internet wormhole with this collection, emerging days later gibbering nonsense, gassy-eyed and unshowered.