I posit his attack was because he — the sea critter — did not want to be filmed. Maybe he or she was pissed off at having his or her privacy invaded.
We all know how that feels, don’t we? I’m thinking of family get-togethers, some person with a ubiquitous camera phone…
Then, when the Australian put on goggles and went back into the sea…he got wacked again! He thinks it was the same octopus.
Since octopuses are far smarter than most of us believe, I’ll bet it was the same one.