Recently, a reader wrote to us about finding “two very strange creatures in soil in my garden near San Diego.” The creatures are “very strange” because they are fairly long – about four to six inches (or 10 to 15 centimeters, roughly) in length – and, perhaps more notably, both were a vivid silver, like mercury (the element, not the planet; hence the lowercase “m”). They also have a thin black strip that runs down the lengths of their bodies. When our reader unearthed them from the garden soil, they “thrash[ed] around.” In contrast to many emails we receive, the reader didn’t speculate that he found some sort of worm; rather, he thought at first that he had found two snakes, but quickly decided this wasn’t the case because the creatures didn’t appear to have heads. (Presumably, the creatures did have heads, but they weren’t readily discernible from the rest of the body.) And so the question of course is: what are these long silver creatures that our reader found?