Seals quite commonly (so the biologists have told us since the kayak event) throw octopus against rocks to stun the octopus into submission. Since there was no rock immediately handy, this (now famous) seal looked around for something that was hard to bash the octupus against, and the kayak apparently seemed to it the best rock substitute going...
..On sea snakes:
I may be one of the very few WP members who have swum with these in the sea - a whole lot of them. We don't have sea snakes in NZ waters (too cool for them). And being a kiwi, we are not intimidated by the sea, shark attacks are extremely rare here.
During a visit to tropical Niue Island in the Pacific, it was a lovely day and I managed to find access to a beach (there are very few there) and dived in. The waters are crystal clear. Floating, I happened to look down and saw about 30 banded black and white snakes circling a few feet below me. They saw me, but just continued what they were doing, whatever it was they were doing - and I returned back to the rocky shore in case they changed their mind about not minding me being there.
I didn't know for some time after this that this snake is one of the most poisonous in the world, however it rarely bites anyone because it has a very small mouth and a placid temperament.
My other water adventure in Niue also ended abruptly when I was paddling in shallows past a cave and a conger or moray eel leapt toward me in a very menacing and fast fashion. I was younger then and could also move very fast - which I did to put as much distance between it and me in the least possible time. That was far more dangerous than the encounter up close and personal with the sea snakes.
My only other encounter with a snake in the wild was in East Texas, as I was wandering through a bird sanctuary and startled a water moccasin, who also startled me. We headed in opposite directions as fast as we could.
Though I have seen seals on the shore of the South Island of New Zealand, there are colonies of them, I knew they can be aggressively territorial and have to be viewed from a non-threatening distance. Colonialists almost hunted them to extinction once for their fur. They have recovered, but now dogs and some violent people - always men or at least the ones who get caught - attack them and injure or kill them wantonly, though the seals are a protected species. Fortunately this is only a tiny criminal element which the rest of the country holds in absolute contempt. Every country has its animal tormenters, unfortunately.