Loopy unknowingly befriends a scientist who turns into a monster on and off without Loopy knowing that the monster is really him.
| Actor | Role |
|---|---|
 Daws ButlerLoopy De Loop (voice) | Loopy De Loop (voice) |
 Hal SmithElderly Woman / Mr. Hyde (voice) | Elderly Woman / Mr. Hyde (voice) |
 Don MessickCar Owner / Dr. Jekyll (voice) | Car Owner / Dr. Jekyll (voice) |