The Intruder

Several days ago, I noticed that something was eating my sorrel. Huge bites out of the leaves had appeared overnight, and little black poops (entomologists call it "frass") speckled the leaves. I searched carefully for the culprit, but I found no one.
Then today I searched again, and found him! A cabbage looper. Except when I found him I didn't know he was a cabbage looper. I had my usual shudder at anything worm- or sluglike. (If it's a worm, I tell myself, "Good worm. Good worm.") My only thought was to rid my sorrel leaves of the intruder. I scraped him off the leaf onto a broken pot shard and then stopped. Was I going to kill him?
Last summer I was really into butterflies. I looked up a lot of butterflies and their caterpillars and marveled at the variety, even in my not-particularly-butterfly-hospitable city. I could not squash this caterpillar without at least finding out who he was.
A short search on the Internet revealed my sorrel-loving caterpillar to be a cabbage looper. They have legs only at the front and the back of their bodies, and move around like an inchworm, hence the name "looper." They eat just about everything, unlike, say, the pipevine swallowtail caterpillar, which only eats pipevine leaves. In fact, they are a serious pest for commercial vegetable crops. And they turn into a boring brown moth. But I just couldn't kill him. So I placed him in the front yard among the weeds, where he'll be sure to find something to eat. And now I can eat my sorrel.