I freaked out when I saw this. The first thing comes to my mind is to destroy the nest but I'm afraid to do so. Luckily MIL was around. When I told her about it, her respond was "Ohhh...this arr" (so calm)
and immediately took the mop stick and poke the nest till it was destroyed. She is so brave. *shame* The nest was built right behind the washing machine. We have been going in and out of the laundry area EVERYDAY but did not even notice it.