When Fred's hillbilly friends the Hatrocks come to visit, even the Gruesomes can't scare them away. Fred finally discovers their aversion to rock music, and uses it to chase them back to the hills.
| Name | Type | Role | |
|---|---|---|---|
| Alan Dinehart (II) | Writer | ||
| Herbert Finn | Writer | ||
| Jean Vander Pyl | Guest Star | ||
| Don Messick | Guest Star | ||
| Howard Morris | Guest Star | ||
| Alan Reed | Guest Star | ||
| Mel Blanc | Guest Star | ||
| Gerry Johnson | Guest Star | ||
| Joseph Barbera | Director | ||
| William Hanna | Director |