The Window Tapper is My New Favorite Halloween Prank!
Oh this thing is awesome! You can hang it so it looks like a peeping clown is outside your window, or maybe inside, welcoming you in! The window tapper has a motion detector so he will tap three times on the window when someone walks by, or you can just turn it to the ON position and he will tap every 10 seconds! I found one on Amazon for around $35 but there are different cheaper versions also. Happy haunting!