Professor Jeffries is the main antagonist of Chill Out, Scooby-Doo!. He is a scientist who was supposedly looking for the Abominable Snowman, but it is revealed that he was actually stealing valuable crystals for his own gain.
He is voiced by Alfred Molina, who also played Doctor Octopus in Spider-Man 2, Satipo in Raiders of the Lost Ark, Johann Tetzel in Luther, Ke-Pa in Kung Fu Panda: Legends of Awesomeness, Mr. Freeze in Harley Quinn, Reverend Leland Drury in White Fang 2: Myth of the White Wolf, Maxim Horvath in The Sorcerer's Apprentice, Lasombra in Hey Arnold! and The Duke in Solar Opposites.