Unexplained voice on baby monitor
Hello, I've attached 3 video clips, the first and shortest one, at approx 10:03:10 what seems to be a voice says something like "ooh cha". Quite loud considering the white noise is also being played by the baby monitor. The second clip is my initial investigation a few minutes after hearing it, and the third and final is me entering to check his cupboard and under his bed as my wife and I were baffled. I think it's important to note that on the video you can't even hear me speaking to him, so the voice/sound must've been quite loud. I can't think of any toy he has that makes that sound and we've never heard it before.
I know it's a WiFi monitor, it does have a push-to-talk function but when it's pressed the white noise cuts out, which in this case it didn't. My kid is only 3 years old and the voice seems too deep to be his. I sent it to a friend and he thinks it sounds like me, I don't disagree either. But I was at the other end of the house brushing my teeth at the time. I've attached the videos to at least show by timestamp I'm not doing anything silly here to get views and to show the volume differences from me coming in the room etc. Hoping someone has a boring explanation please!