Certain kinds of ants, called sanguinary ants, raid the nests of other ants and carry away their larvae. When the captured ants become adults, the sanguinary ants force them to work as slaves, chewing food for their captors!
Another type of sanguinary ants send their queen into the nest of other ants. The queen kills the queen of the raided nest, then lays her eggs in the new nest.
The newborn sanguinary ants are then raised by the slave ants. Eventually, the sanguinary ants completely replace the other ants in their own nest!