Really Really Stupid XD

Okay heres a general idea of what happened (dont do this!!!):

Okay so I made the smoke bomb mixture as usual, except I stirred it for a VERY long time (like 5 minutes extra) so it ended up all the wrong color, and marshmellowy and weird. I had no idea what it was gonna do. Anyway I put it in a metal container (I won't tell you what for safety reasons, suffice to say that it was very thick) and then closed it and drilled a hole in the top about 1.75" in diameter. Oh yes and I also put a 5 short pieces of crackling fuse in the center of it. Then I added the fuse, put it through the hole and let it cool. While it was cooling I lit the disposable mixing device and found the mixture to actually work better than if it was not overcooked. Then I dug a hole, stuck it in and lit it. As the fuse burned I sprinted away to watch it. It started smoking quickly and in about 2 seconds it exploded. It was dark, so I'm not sure what happened but I think that I saw pieces flying around. Anyways people started coming out to see what happened so I bailed, leaving it in the hole in the ground. I came out later and tried to see what happened but couldn't find anything unusual. The container was still there and there was nothing around. I knew from the disposable mixing device (I had used a cardboard piece) that there was no way it could have burned that fast. So I took it inside and opened it (with ALOT of effort I might add). And found the inside empty. I have no clue what happened, but it was awesome. The container also had no signs of damage on it at all, which was weird. Anyways I've been forbidden to ever do it again (yah right). So I learned a pyro lesson which I will pass on to you:

Lesson #1: Don't contain the Potassium Nitrate mixture or it will explode. If you do contain it, be sure to use alot of caution. Better safe than living with 8 fingers or one eye!