Dowsing rods, or divining rods, are sticks made of conductive metal. Mine are copper. You're supposed to be able to use them to communicate with spirits, but it's a whole thing. You hold the rods as still as you possibly can, and ask the spirits what a yes and no answer will look like. With any luck, the rods move and cross in different directions, one way for yes and a different way for no.
I was shocked and horrified when the rods moved for me.