Huge as they are, rainbow squids still have a few enemies, chief among them an ancient evolutionary success story. Sharks have been hunters of the oceans since Devonian times (but with a possible Silurian record), around 400 million BC. They are survivors, sleek and efficient, and have outlived all the mass extinctions that have occurred during their time of existence, adapting to whatever new aquatic environment presents itself. The simple, primitive design of the shark and its brutally straightforward lifestyle have ensured its survival.
With the formation of Novopangea and the resulting vast ocean mass, there are new problems for these marine hunters. Shark food is now widely dispersed, with huge stretches of empty water between. A single shark hunting randomly is unlikely to come across enough prey to sustain it and may be unlucky enough to starve. But many sharks hunting over a large area are in a better position to meet a food source. When they do, if they are able to communicate the presence of food to the others, the whole shark population benefits. The sharkopath has evolved just such a method of communication.
The Global Ocean is patrolled by loose groupings of sharkopaths covering a large expanse of water. If one happens upon a prey animal (such as a rainbow squid), it sets off a flashing sequence in bioluminescent patches along its side. This visual signal penetrates the water and can be picked up by the sharkopath's closet neighbor. The neighbor repeats the signaling process and soon the whole group of sharkopaths is aware of the presence of food and starts to home in on its quarry.
In defense, a rainbow squid can camouflage itself to blend in with the water as soon as it notices the danger. Despite this remarkable camouflage, a marauding group of sharkopaths - armed with an incredible array of senses, and with the added advantage of strength in numbers - stands every chance of overcoming the squid's defenses.