Nightmarish "supersoldier" ants with huge heads and jaws have been created by activating ancient genes.
Scientists believe the monster ants may be a genetic throwback to an ancestor that lived millions of years ago.
Supersoldier ants can occur naturally in the wild, but only rarely. In the deserts of America and Mexico, their job is to protect the colony from raids by invading ants.
Scientists showed that ordinary ants of the species Pheidole morrisi contained all the genetic tools needed to turn them into supersoldiers, which were induced by dabbing larvae with a special hormone.
The research is reported in the journal 'Science'.
Authors Dr Rajendhran Rajakumar, from McGill University, Canada, wrote: "We uncovered an ancestral development potential to produce a novel supersoldier subcaste that has been retained throughout a hyperdiverse ant genus that evolved 35 to 60 million years ago."