Pareidolia and unless you made it yourself, you can't leave out the possibility the recording was faked. Researcher bias is a huge factor when perception plays a key role in the interpretation of evidence. It is not just RF ingress with EVPs but CODEC noise. The sampling rate of those little recorders is only fair. The analog to digital conversion introduces lots of low level noise.
Consider also that some people claim to hear this when they play Stairway To Heaven backwards. Go figure.
Oh here's to my sweet Satan.
The one whose little path would make me sad, whose power is Satan.
He'll give those with him 666.
There was a little tool shed where he made us suffer, sad Satan.[