Death watch beetle
The deathwatch beetle (Xestobium rufovillosum) is a species of woodboring beetle. It lives in pieces of wood and can sometimes be found in the wooden parts of old buildings. The adult beetle is brown and about  long. Eggs are laid in dark crevices in old wood inside buildings, trees, and inside tunnels left behind by previous larvae. The larvae bore into the timber. Larvae  feed for up to ten years before pupating, and later emerging from the wood as adult beetles. Timber that has been damp and is affected by fungal decay is soft enough for the larvae to chew through. They use enzymes present in their gut to digest the cellulose and hemicellulose in the wood.