A 45 kg. (99 lb. — but who exactly weighed him?) Giant Pacific Octopus last November became annoyed, and was filmed attacking a $200,000 remote controlled submarine being used for salmon research off the west coast of Vancouver Island.
The aggressor would have been Enteroctopus dofleini, a species which can be much bigger. The Giant Pacific Octopus is rumored to reach 30 feet (9.1 m) across and be capable of weighing more than 600 pounds (272 kg), the record specimen actually weighed 400 pounds (182 kg) and had an arm span of 25 feet (7.6 m).
Hat tip to Glenn Reynolds.