Peripheral vision caught me again, calling my attention to the side, when I'd been intent on moving down the sidewalk. This time, a tiny movement inside a a ceramic bowl that was left outside during a rain slowed my steps. The bowl contained about half an inch of water, a large wolf spider, and a pile of squirm.
Interesting: I've never seen a pile of squirm before.
I tipped the bowl over onto a rock in the garden, thinking the spider might still be alive since the water wasn't especially deep. In fact, I wondered why she hadn't just crawled out--it wasn't like the depth was over her head. The spider didn't move. The pile of squirm separated itself into two smaller squirmy piles, and writhed around on the rock for a while, before crawling into a crack in the damp earth.
In the video, the spider is well-camouflaged and hard to see, but she's on the left side of the screen, about midway down.
At the time, I was completely mystified. How did two strange-looking worms happen to end up in the same bowl as an enormous arachnid? I wish I'd paid more attention to the spider, because now I know the connection between everybody in the bowl. The squirmy things are a couple of horsetail worms. These members of the roundworm family parasitize insects, spiders, and similar organisms. Apparently, having these little guys inside you makes you thirsty, so you hang around water a lot. When the worms are ready, they emerge, killing their host, and swim away in the pool of water nearby. There, they lay their eggs on vegetation in the water so the cycle can start all over.