UFO's didn't have usernames. Early in the day if they spoke, we'd see "Undefined: [insert chatter]" and then I believe they fixed it so we could see: UFO 6: [rawr]...
It wasn't uncommon that some couldn't see the ufo despite another being able to. I loved that "the UFO really is still there!"but-it's-not glitch..
...Although it was possible to have the UFOs have usernames in the past by getting in your mini-ufo and hiding underneath so that your username showed below the UFO. I did that once, and actually fooled someone. I got a kick out of that.
Proof:

I was also fond of the "UFO-Clone" glitch like this one:

There was one time, I believe it was Sorn who did that in 1000 and basically filled the whole screen with UFOs and caused hysteria. It was awesome.