Farligt Venskab (1995)

A dying elderly scientist proposes love-sick Jonas a cure that will improve the youngster's physical skills and general sex-appeal. What the scientist really aims to accomplish is a body switch: he wants to survive in a young man's body and gladly leaves Jonas to wake up in his own wasted frame. Jonas must somehow signal his predicament to his friends. Both men rev up for a survival-of-the-fittest chase.