To impress a beautiful girl, Harold Kelp, the grandson of professor Julius Kelp, who created a potion to transform his personality, gets his hands on his grandfather's secret elixir and unleashes his destructive alter ego, Jack. Drake Bell, Jerry Lewis, Tabitha St. Germain, Logan McPherson, Jarrod Young, Brian Drummond, Andrew Francis Added on Amazon Prime 2020-12-18. Youtube Trailer