Lucky guess? Or unlucky depending on how you look at it. Either way, it's icky.

That's never happened to me before. I have no idea why it would have done that, either.

LMFAO!!!!

Sorry i just take that really funny right now.....but if it was me in that situation i would probably drop kick the milk across the room....then put the cap on it and see if it pops off...

It's also possible that the cap was too small by some chance defect at the factory and when you put it on, the stress just built up until it shot off. It wouldn't have happened before because it was held in place by the little pull-offy-thingy (technical term). That also explains why you haven't died of food poisoning.

Haha, wow. I can honestly say that the milk in my house does not do that.
Maybe you have a poltergeist?

lmao.. the milk wasn't bad I sniffed it because I was thinking that too after I was done poking and prodding it.

as for the cap being defective or too small that would make sense but if that were the case why didn't it happen the day after when I used the milk again?

all these suggestions on what was wrong are good but the only one that seems to fit is that my milk was gassy, maybe it had indegestion that night? hehe

Temperature change, shrinking/expanding of the bottle. That's the only explanation.

oh i'm sure there are more explanations if we all sat down and put our heads together.

temp change would have to be pretty drastic to produce that effect so many times in a row and it was a normal temp so i dunno.

shrinking/expanding is deffinately possible, but i still think it's more fun to think my milk is possessed or has gas :P

Well, you said you set the cap on it, not screwed it on. So maybe when you pushed it on, the bumps on the cap lined up with the dents on the bottle (the tread parts) so that the cap didn't really fit, and that's why it flung off. And you haven't been able to recreate it because the bumps just aren't lining up right, or the cap got a little stretched out from you making it do that over and over the other night.

Wait, I have further research to add to this mystery...
On a dark and stormy night a few weeks ago, I was making sushi, and my boy was drinking a beer. He finished his beer, popped the cap back on loosely, and a few seconds later, there was a pop! and something hit the soy sauce dish and spewed it all over me. I fished the beer cap out and we had a good laugh about beer ghosts.

We figured that the glass bottled had been cold when it was full of frosty beverage, and when he emptied the bottle, the glass began to warm rapidly and the air pressure inside changed enough for the loosely replaced cap to be forcibly flung into my soy sauce. Also, sour milk isn't POISON, persay... just gross. The same bacteria that make your milk bad are in cheese and yogurt, so its kind of silly to say its poisonous and comotized could have been in danger. Paranoid much? :p
I don't think it was the buildup of gas, or the cap... I think it was the air in the jug warming to room temperature and expanding, until the very light seal created by the water pressure ("milk" pressure?) between the damp cap and the mouth of jug was broken.

Mystery solved? :3

Maybe your milk is haunted. The ghost of cows past or something.

lmao.. the ghost of cows i hope to god he doesn't get pissed off and decided to jump on me in the middle of the night! :P

paranoia is a good thing sometimes, it helps keep us alive when we would otherwise do something stupid and die. but i do agree that bad milk is not poison, i love yogurt, cheese and *gasps* dare I say it? cottage cheese which IS rotted milk, no if ands or buts about it.

And yes, your theory makes more sense to me, plastic can't expand or shrink that fast without a moderate temperature difference been the refrigerator and room air BUT the air inside of the jug isn't what one would call 'thick' considering the fact that we can't feel it if we poke around in it, if we could we'd all die from asphixiation :P

what would a ghost cow sound like anyway? moo or mooOOOOOOO <- long drawn out creepy version of a cows normal speaking voice. Yes, they speak, moo might not mean much to you but it damn sure gets their conversations started!

muahahaha