Watch Monster Hammerheads: Killer Instinct (2023) HD Full Movie Free on SolarMovie. Watch Monster Hammerheads: Killer Instinct (2023) online free. Dr. Tristan Guttridge believes hammerhead sharks can reach monster sizes by hunting other sharks -- ...Dr. Tristan Guttridge believes hammerhead sharks can reach monster sizes by hunting other sharks -- but the only way to prove it is to get tissue samples from some of the largest sharks on the planet.