I have only just recently learned to look for and appreciate caterpillars. There are some crazy looking caterpillars out there too! This is one great example:
Pipevine swallowtails (Battus philenor) are one of many species of caterpillars that use a stinky eversible horn called an osmeterium as a defense against predators. The fact that they are bright yellow against their purple-black bodies makes the osmeteria incredibly striking. What a beautiful animal!