City Gophers
City Gophers like gophers, they eat the trash which was thrown by people and they bring trash back to their cave. After locked the City Gophers, it will deliver a signal to the Gophers Probe (a device in the hands of street cleaner) to remind street cleaner where trash can is full, and City Gophers down to underground also prevent to people still throw the trash and emitting a stench or other problems. City Gophers prevent those problems.