Don't Fool With a Phantom - S2-E8
Shaggy: Hey, Scoob, aren't our wax statues the greatest?
Scooby: Yeah.
Daphne: Just what are you fellas going to do with those wax dummies you made?
Shaggy: Well like simple, next time we have a mystery, those dummies can go instead of us.
Fred: There's only one problem. How to tell one pair of dummies from the other.
Shaggy: Very funny, very funny.
Scooby: Yeah. Rery funny.