oyster mushroom growing kit for his birthday. It's a cardboard box full of coffee grounds and ... whatever it is that mushrooms come from. When you're ready to grow it, you slit open the plastic bag inside and moisten the coffee grounds. Voila, mushrooms!
Instead, we left the unopened box in the living room for a couple months. After a while, we put it on our dresser and forgot about it for another month. And then one day ... there was a mushroom growing out of the corner of the box.
Did I mention that the kit comes inside a sealed plastic bag*?
After a few days, we opened up the box and found not a pile of coffee grounds, but a mass of solid white mycelium and a bunch of stunted, mashed together mushrooms. They'd grown to fill up all the space in the box (and to enclose the little plastic spray bottle stuck in there).
BEST PET EVER!
We started reading about growing mushrooms on coffee grounds, and discovered that we could probably recycle our kit and morning cuppa into fancy mushrooms for as long as we cared to (TreeHugger, The Funny Farm, and the amazing Mad Bioneer, who, among lots of fascinating mushroom info, mentioned that oyster mushrooms are carnivorous.)
*There are, in fact, mushrooms that eat plastic.