Related Clues:
- MI6 concern
- US rodent
- Target of an exterminator's smoke bomb
- Tunnel excavator
- Facial mark
- Skin imperfection
- Beauty mark or burrowing animal
- Tunnel-creating creature
- Blind burrower
- Insidious insider
- Tunneling mammal
- 18-Down, at times
- 'The Wind in the Willows' figure
- Spy story staple
- Secret agent being underground