Surströmming, the Swedish can of fermented fish, is strongly recommended to be punctured while submerged in tap water. It is not pasteurized and is actively fermenting in storage, and the content will spray around if opened under atmospheric conditions.

When transported on cargo flights, they are double packed as cans in a barrel in a crate, and considered UN classified "miscellaneous dangerous goods" with identification number UN3334 "Aviation regulated liquid, n.o.s." with accompanying scary(albeit monochromatic) warning stickers, if at all accepted. When transported on ocean going vessels, they are often required to be in its own shipping container, again double packaged and correctly labeled.

It is also mostly eaten outdoors :)

You forgot to mention that it is actually quite delicous.

I hope you didn't find that first paragraph out the hard way today!