The walls don't have ears, they have pee streams.

It's pee-back time.

Sick of drunk partiers peeing all over their walls, the residents of St. Pauli in Hamburg have decided to fight back. If you are going to pee on their walls, their walls are going to pee on you right back.

Thanks to a special hydrophobic paint, a stream of urine forcefully projects right off the wall and directly onto the urinator's shoes. Locals are calling the campaign "St. Pauli pees back."

Sources: The Local