So, what is wrong with this beer?

Back story is that a friend bought a 6 pack of this commercially brewed porter and said he couldn't manage to pour it (or drink it from the bottle for that matter) without having it explode everywhere.

He gave me a bottle and I chilled it in the fridge for a few days. I took it out and opened it. Nothing exciting happened, but there was visible CO2 vapor exiting the bottle.

I poured it slowly and managed to get about half the glass filled before the whole thing (the part in the glass) went from liquid to foam. The CO2 bubbles in the head are huge and the head is thick. You can spoon it out like cool whip.

I tasted the beer and it has a very slightly sour taste. I'm no expert on sour beers but it had a very faint taste that reminded me of the few sour beers I've tried.

I'm guessing it has an infection of some sort. Any idea what? I guess the main culprits are Lacto and Brett?

Pics to follow...

Here are a few pics:

Could be an infection, I'd wager it is but I don't think I can say for sure. If it is a local brewery you could probably stop in and they'll exchange it for you if you show them the issue. If not, then you might be able to return it to the liquor store you bought it from, but I don't really know how that would go over.

I had a few Drakes (same six pack) that did that.