Anti-predator outgrowths are found prevalent in animals such as stinging spines of caterpillars. However, an encounter with a predator is usually fatal as caterpillars would die easily even if just small body parts were taken. Here, we showed the larvae of Phrixolepia sp. did not get injured when the fleshy but not urticating scoli were removed. By showing the morphologic traits, we assume these particular scoli function as enlarged warning signals and substitute to be attacked so that caterpillars can warn multiple predators, with a lower chance of getting injured when encountering natural enemies, such as birds and carabid beetles.