A fantastic story from the US... more like this, please, yanks...
Mrs. Bergstrum the biology teacher clearly checked the wrong box when ordering dissectable fetal pigs from hog-bit providers Edmund Scientific.
What showed up instead was a reinforced drum of full-sized adult pig heads swimming in their own facial sweat. Making the best of her mistake, an attempt was made to dissect these in class, but this failed miserably as no one could get through the skull.
Sensing potential, someone slipped accidentally on purpose, a pig head ended up on the floor, a head was thrown, a girl screamed, and things went from bad to worse.
Soon enough, the unused heads began to disappear from their storage cabinet and show up in girls' lockers, the ball bin at the gym, staring up sadly out of the toilet bowl, etc.
For a few days, these heads were everywhere.
Interest waned when the fruit flies arrived.

Our Biology class ended up doing the fetal pig dissection at around the same time as our English class was reading Lord of the Flies. By the afternoon, there was a line of little heads on the ends of pencils in the garden outside the school. It was beautiful.