Crazy Ice

So, a strange thing occurred this afternoon as I made some ice cubes, thinking I might want them now that the weather is warmer.

This is normally a very boring thing. Fill ice cube tray, stick in freezer, ice cubes produced in an hour or two.

Today, this happened.

Zoomed in:

What the what? It would be (slightly) more understandable if *all* of them did this. But nope. Just this one and a little frost around a few others. I can only surmise it is a related phenomena to this, and that I happened to place the tray in just the right place for it to be vibrated by the motor. 

Either that, or Elsa from Frozen has taken residence in my freezer.