Scientists have managed to trigger a predatory gene in mice, leading them to act like "zombies."
In a study based on mice brain circuitry, researchers were able to isolate neurons that tell them to pursue prey, Live Science said.
They were also able to isolate another set of neurons which tell the mice to bite and kill.
Scientists then used optogenetics, which is a way of telling neurons to fire when they are stimulated, to make the mice attack.
The mice would attack anything nearby when they were stimulated by a laser. However, they did not attack one another.
Lead investigator Ivan de Araujo from Yale University School of Medicine said: "We'd turn the laser on, and they'd jump on an object, hold it with their paws and intensively bite it as if they were trying to capture and kill it."
This also removed their natural preferences for edible over nonedible objects, however mice that were hungry would be more aggressive.
Scientists could also isolate neurons so that the mice would only hunt an object and not kill it.
The researchers have said they will now look at how the two sets of neurons, pursuit and killing, are coordinated.
De Araujo said: "We now have a grip on their anatomical identities, so we hope we can manipulate them even more precisely in the future."