Calosoma scrutator, also known as the fiery searcher and caterpillar hunter,[1] is a species of ground beetle belonging to the genus Calosoma, subgenus Acalosoma. This beetle can be as large as long.[2] The distribution of this species is relatively widespread, and is common in North America.[3] The adult beetle is known to excrete a foul-smelling oil when it is handled. The oil has been described as smelling similar to rotten milk or rancid olive oil.[4]