What is the deal?

I am blogging today strictly to get this off my mind and find some peace with it. My classroom has been pretty peaceful since Christmas with the one boy gone to alternative school. It has really changed the whole dynamic of the room. Now, we aren't angels by any means (ha!), but we are a normal classroom now with occasional problems.
Today, one of my kids just flipped out! I really don't know how else to explain it. He did this about two weeks ago too. It comes out of no where - no warning at all. He was having a great day - as a matter of fact, hasn't been in trouble at all in over a week and a half (this is a big deal for him! ha!). Anyway, we are working on science, and I am even giving them hints on where to look for answers. I mean - could I make it any easier? well, I guess I could do it for them!
They had earned some outside time today. (b/c come on - it's the first day of spring and so nice outside) I promised and I hold my promises. However, they had to finish science first, and I warned them not to turn in any old thing - I wanted neat and evidence they had tried. Well, come time to go out for the last 20 min. of the day, and the ones who tried to slip a fast one past me and not even read the freakin' questions (they couldn't have from the answers), I told them to find a bench and try again and then they go play. I even went so far as to tell where to find the answers and circled the ones they needed to try again on. And he flipped out! Slammed his papers down - stomped - yelled - mumbled - basically acted like a crazy person. I wish I had it on video to show just how badly he flipped out. We were close to the 2nd grade hall and his 2nd grade teacher came out to get him (she has permission from the parent to spank him). He started screaming and yelling and having such a fit that 5 different teachers poked their heads out to see what the heck was going on. He was screaming, "Call my Mom! I don't give a f***! I don't care! Call her!!!" Of course, when the other teacher grabbed her cell phone, he got quiet. Then when his Mom wasn't at her desk, he started taking everything out of his backpack and throwing it against the wall and yelling all kinds of crazy stuff the whole time. I am telling you - there is NOTHING that should have set him off this badly!! I am still wondering what could be so bad that he had to act that way? Did he just get so worked up that he couldn't stop?
It makes me sad that there are kids out there at 9 years old that have this much to be mad about! If this is how they handle their anger now, what are they going to do when they are older? It is really scary!! And it is just sad!
*Ignore any typos- I'm not proofing - just had to get it out and let it go - now I'm going outside! woo-hoo!