The longhorn crazy ant (Paratrechina longicornis) is a species of small dark-coloured insect in the family Formicidae. These ants are commonly called "crazy ants" because instead of following straight lines, they dash around erratically. They have a broad distribution, including much of the tropics and subtropics and are also found in buildings in more temperate regions, making them one of the most widespread ant species in the world. They do not sting people.