I saw a Spicebush Swallowtail (Papilio troilus) laying an egg on a Sassafras leaf, and decided to follow it through its life cycle. The caterpillar initially mimics a bird dropping so it sits in the appropriate position on the upper surface of a leaf. Some may think looking like shit is a high price to pay for survival. Later in it's life cycle it grows to large for the bird shit ruse to work, and after a subsequent molt it resembles a small snake, and then it hides on the leaf's underside. It continues with the snake impersonation until it pupates.