after playing the piano I got up and saw this beetle on my wall! I hope it doesn't eat wood! PS it doesn't have 4 antenna - just two - the others are shadows!
I think this may belong to the Conoderus genus of click beetles. Adult click beetles feed on nectar, pollen, flowers, and sometimes soft-bodied insects like aphids. Click beetle larvae are mostly predators on small soil animals, but some eat roots and seeds. So your piano should be safe.