This appears to be a scuffle between two octopuses over a nice cozy place to sit and blend in with the scenary. You see provocation, chase, and some smacking about, plus some color-changing, which might be communication, a cooling-off, or bragging. Who knows? There’s also an intriguing bit where an octopus wipes itself down.
I can’t even tell who won, because how do you tell one shapeshifter from another? Anyway, it’s a pretty cool sequence. This all happened off the coast of Asu Island in Indonesia. -via Metafilter