A little while back, a reader wrote to us about a strange, spiky creature he found in his greenhouse. The creature was about four inches (10 centimeters) long, and it had a red head with spikes on it. (It was “spikey,” to use the common misspelling.) The creature also had pincers near its mouth and three pairs of legs on the front portion of its body. The reader only ever refers to what he found as a “creature,” indicating that he doesn’t know what it is (which of course he wants to know), and he also asked if he should be concerned about planting vegetables again in his gardening operation in light of the creature he found. The reader did not send a picture, making a difficult question even harder to answer, but we are all but certain he found some sort of caterpillar. So, the question before us is: what kind of grey caterpillar with a spiky, red head did our reader find, and is harmful to his garden?