Mouse

Mice are fast and small enough to lose against a lit tunnel floor, so the squeak is usually how you notice one. The reliable spot is in front of exposed Living Wood Walls below the surface, where they turn up far more often than in ordinary caves. Ice, jungle, hallowed and evil ground produce none at all.

Unlike most critters, nearby town NPCs suppress mouse spawns, so the cozy underground house you built next to your hunting ground is working against you. The Living Wood Wall spawns ignore that rule completely, which makes an abandoned living tree the best place to hunt even in a settled world.

Netted mice can be released again later or built into a cage, though building one is a one way trip unless you shimmer the furniture back apart. Statue mice cannot be netted at all, they vanish in smoke when you try, so a statue is decoration and not a farm. A rare golden variant exists and is worth stopping for.