A scientist develops a formula which will cause animals to regress to the form of their primitive ancestors, and tries it on himself with disastrous results.
| Actor | Role |
|---|---|
 Robert ShayneProf. Clifford Groves | Prof. Clifford Groves |
 Richard CraneDr. Ross Harkness | Dr. Ross Harkness |
| JJoyce TerryJan Groves | Jan Groves |
 Doris MerrickRuth Marshall | Ruth Marshall |
| RRobert LongGame Warden George Oakes | Game Warden George Oakes |
 Tandra QuinnCelia | Celia |
 Beverly GarlandNola Mason, bar waitress | Nola Mason, bar waitress |
 Dick RichSheriff Andy Andrews | Sheriff Andy Andrews |
| LLee MorganCharlie Webb, bar owner | Charlie Webb, bar owner |
 Frank GerstleMr. Wheeler, hunter | Mr. Wheeler, hunter |
 Robert EastonDanny, a townsman | Danny, a townsman |
| EEric ColmarBuck Hastings, a townsman | Buck Hastings, a townsman |
 Robert BrayJim Newcomb, a townsman | Jim Newcomb, a townsman |
 Anthony JochimSkeptical Naturalist | Skeptical Naturalist |
 Marshall BradfordNaturalists' Conference Chairman | Naturalists' Conference Chairman |
 William FawcettDr. Fairchild | Dr. Fairchild |
| TTom MonroeThickset Townsman at Webb's Cafe | Thickset Townsman at Webb's Cafe |
| AAnn StauntonState Trooper Dispatcher | State Trooper Dispatcher |