My teenage son is involved in a live-action roleplaying game (imagine people dressing up in costumes and acting out D&D-type adventures). They use foam "weapons", and represent throwing "magic spells" by tossing little cloth packets of birdseed. For uniform packing, my son prefers to use plain white millet seeds (which look astonishingly like hemp seeds, but that's another story entirely). Recently he borrowed my car to drive himself and a few of his friends to one of these adventures. Apparently while he was driving, his friends were making seed packets in the back seat, and managed to spill a fair amount of seeds all over the rug. The next day, he *said* he'd cleaned up most of it. I didn't pay very much attention to the back seat; mostly I was just in a hurry to drive off and do some errands. A few days later he borrowed my car again. When he brought it back to me, there was a mostly-empty spring water bottle rolling around on the floor, which I promptly got rid of myself. I didn't notice that the bottle had leaked onto the rug. The car sat in the hot sun for a few days, while I continued to not pay attention to the back seat. Today, though, I had to haul a number of bulky items home, and I went to put them in the back... and discovered that the millet seeds, on the soggy wet rug, in the warm sunny car, had begun to sprout! Yes... my VW has turned into a giant Chia Pet.