His two front teeth!
Well not really. But he's starting to lose more baby teeth. As the adult teeth come in they push out the milk tooth. Tonight at supper time I heard something rattling around in Steele's food bin. I went over and found this:
I have it sitting on the windowsill of the tack room. It's the first one I have seen. He didn't seem bothered by it all.
Now he just needs to take care of them.