You’ve already got that awesome, high-speed cardboard robot cockroach, so here’s a rodent companion for it to play around with. Beware though–this robot rat is designed with the explicit purpose of making other animals stressed, depressed, and otherwise upset.

With the intent of studying how mental disorders affect lab rats, the Japanese researchers programmed this robot to constantly harass its neighbors into a state of submission. More on their methods, from New Scientist. 

The researchers tested WR-3’s ability to depress two groups of 12 rats, measured by the somewhat crude assumption that a depressed rat moves around less. Rats in group A were constantly harassed by their robot counterpart, while the other rats were attacked intermittently and automatically by WR-3, whenever they moved. Ishii’s team found that the deepest depression was triggered by intermittent attacks on a mature rat that had been constantly harassed in its youth.

The team say they plan to test their new model of depression against more conventional systems, like forced swimming.

Can you imagine what a human version of this would be like? Something like this guy, perhaps.