You've never seen such a sight in your life. A team of scientists used brain control to turn about a dozen ordinary mice into killing machines. They employed a technique called optogenetics that manipulates neurons using light to make the fluffy critters go all Hulk on prey. With the switch off the light, and the mice were mostly chill, sometimes even scurrying around their cages to avoid prey or toys made to resemble prey. But when the switch was on, and things got ugly. Crickets in cages were attacked and beheaded, and plastic toys that looked like prey received powerful bites that would've been lethal. The scientists are not trying to create a monster. “Basically, we are trying to understand