My Echo somehow woke up when we were in another room, then heard itself talking to itself, and called my friend in the middle of the night. You can see the log of what it said and how it heard the last word as the command: https://www.facebook.com/mike.deeks/posts/10215464075417775

It was both hilarious and infuriating. I immediately turned the calling feature off (you have to contact support btw) and later we switched to Google Home.