I seached, but the only references I can find are to attempts with heavy and enthusiastic rubbing.
I think I’m going to go delete my browser history now…
The octopus (of various species) is a highly intelligent creature capable not only of being trained but of developing ways of communicating with humans. Cousteau’s Octopus and Squid (not the definitive treatment but what I have immediately at hand at this lonely hour) describes various crew members “making friends” with octopuses, where they rapidly become accustomed to human presence and perform “tricks” to earn rewards, including complex mechanical problem solving.
I’ve never developed an extended relationship with an octopus, but on a few occasions while diving I’ve come to a kind of detente with these noble beasts, in which we eye each other warily. On one occasion, I played “footsie” with an octo; he (or she) would reach out with a tenticle, grab a finger and pull on it, then let it go and grab another. Other divers have reported having octopuses familiar with humans climb on them.
The octopus may be more intelligent (in terms of conceptualization and ability to communicate) than the higher primates. I daresay we have barely tapped their abilities, and the alien nature of their normal experience serves to undermine our estimation of their actual comprehension. Despite being solitary creatures they have extensive social rituals and abilities to communicate abstractions to one another. Certainly, their body structure and particularly the eye and brain are every bit as complex as higher mammals.
I wouldn’t recommend keeping one as a pet, though. They have a great capacity for escape (read Cousteau on that) and despite their loner nature they need room and occasional contact (but privacy from) other octopuses to maintain a healty disposition. Also, the common octopus , octopus vulgaris, like most octopuses, only lives about three years or thereabouts, the notable expections being the large O. dofleini and the giant O. apollyon which live considerably longer but aren’t going to fit in any standard aquiarium. I’d prefer that you leave them free and just visit now and again. They certainly aren’t domestic animals, adapted to living amongst humans or in artificial environments.
Stranger
You’ll just have to take my word for this:
I saw Richard Leakey (sp?) speak at Central Michigan Univ. He said that elephants bury their dead; i.e., they cover them with sticks and branches and stuff.
He then went on to explain that elephants are aware that humans are somehow different from other animals because elephants will bury humans and that humans are the only non-elephant animal that elephants will do this to.
He ended that with the humorous remark that sometimes someone who has been drinking too much to wake up and find himself covered with branches and tree limbs and caught there until someone happens to come along and rescue him.
I had a cat that would sit and listen with rapt attention whenever I sang and played Mr. Bojangles on my guitar. He had sort of a dreamy expression on his face.
A couple of years ago a Doper made a similar quip in a much more sinister (and amusing) manner. I wish I could remember it, because it would be good for a laugh. 
Poor octopus!
I’ve read a fairly large selection of anecdotes regarding complex behaviors in octopuses, including apparent play behavior (using their funnels to push underwater objects around) and interactions with handlers. Eugene Linden’s book The Octopus and the Orangutan contains a number of these stories (and is a lot of fun to read besides).
Blech. I think cats must know exactly how disgusting their crap is, since they seem to use it as punishment fairly frequently.
This reminds me of an incident in my college days, actually. Two guys I knew (S and B), who had gotten an apartment together with a couple of other guys, had decided to start feeding this squirrel that hung around outside their building. This squirrel eventually became so habituated to being fed by them that it would sit on their windowsill and wait expectantly for treats.
One day, after this had been going on for a while, the squirrel appears at the open window while the four guys are all potato-ing on the couch watching some football game.
S says, “Hey, the squirrel’s here. Go feed it.”
B says, “Nah. You do it.”
S says, “I’m not gonna do it.”
This senseless conversation continues for a while, but no one leaves the couch.
After waiting for a few minutes, the squirrel realizes it’s not going to get fed, and clambers into the apartment, where it sits on the kitchen table for a minute.
S: “Dude, the squirrel came in.”
B: “That’s bizarre.”
S: “Maybe we should feed it.”
B: “Nah, let’s see what it does.”
Guy #3 (henceforth called N): “I told you feeding the squirrel was a bad idea.”
The squirrel waits for a minute longer, then jumps off the table and ambles off into the apartment. It’s gone for a few minutes, then comes back through the kitchen, gives everyone one last withering glance, and leaves through the open window.
S: “Huh, that was weird.”
B: “Dude.”
Later that evening, as the four guys are preparing for bed…
S: “Hey, what’s this stuff on my bed?”
B: “I dunno, I’ve got some too.”
S: “Argh! It’s squirrel shit!”
B: “Arrgh! It is! That’s so gross!”
N: “It didn’t dump in my bed. Must be 'cause I’m not the one who feeds it.”
The scene devolved from there (if possible), but I was extremely impressed by the squirrel’s acumen.
What a great thread, one of the most enertaining threads I’ve read in GQ ever.