Weird sound over the monitor

Alena

I don't have a video monitor, I don't want one. I have a simple sound monitor the baby's room is right next to mine. Last night my husband and I were just about to fall asleep sometime around 11:30pm and all of a sudden we couldn't hear the white noise that was playing on the monitor anymore and some weird loud clicking sound came on the monitor (it wasn't really like clicking but that is the best I can describe it). I ran out of the bed because I am closer to the door than my husband is he is pressed against a wall I'm at the edge I busted open the baby's door. He was sound asleep not making a peep the white noise was still on and I looked around I even looked right at his room monitor and nothing was there so I peeked my head inside my room and asked my husband if the sound was still going he said no it stopped once I entered the baby's room. Needless to say I picked up the baby and he slept with us last night. I felt so freaked out just wanted to share with someone. What do you think it could be? I thought maybe we crossed frequencies with someone else but that wasn't the case and also nobody has a baby around my block to use a monitor. Anyone else have a similar experience? Not sure what category this goes under