Dowsing rod

A dowsing rod is a piece of wood resembling a wishbone or a Y shape that is claimed to have the magical ability to find underground treasure.

Mainstream Smurfs Media
In a one-page Smurfs comic book gag, a Smurf is seen using a dowsing rod in the Smurf Village to find treasure somewhere underground when the rod suddenly points downward to a place where treasure may supposedly be found. The Smurf finds what he calls "magical water" that somehow makes whoever drinks it rather tipsy. However, what they do not know is that they have discovered Papa Smurf's underground distillery where he is in the process of making sarsaparilla wine.

In the Smurfs cartoon show, the treasure-hunting imp from "Smurfette's Dancing Shoes" has a dowsing rod which he uses to find the secret chamber of the Treasure of the Lost Trolls, only to find it being guarded by a spirit that will only allow access to the treasure if the seeker finds either three valuable items spoken of by the spirit, or that the seeker marries a fair maiden of a pure heart.