"You’re Gonna Need a Smaller Boat!"

Nanoshark

Scientists using nano technology to shrink objects to microscopic size use their science on a deadly shark, which is injected into a person's bloodstream in an attempt to cure a rare blood disorder. When the shark begins to do more harm than good, a team of adventurers enter the bloodstream in a shrunken submarine in an attempt to kill or be killed by the smallest great white of them all!