In a recent attempt to fool sensors and cameras that identify when someone is trying to buy products at an Amazon Go marketplace, some of the company’s employees dressed in bright yellow Pikachu costumes, according to Bloomberg. As the people picked up sandwiches and drinks in feigned hope of not getting caught, Amazon was able to identify who they were and charge their Amazon accounts for their purchases, Bloomberg’s sources said.

Amazon Go is an ambitious attempt by the company to build out a retail presence without actually relying upon cashiers. Instead, Amazon Go stores, which are currently in testing, would stock products for customers to buy and let them walk out once they pick up what they want without ever seeing a cashier. Sensors, cameras, and other technologies in the store will identify the customers and automatically charge their accounts for whatever they walk out of the store with.

Get Data Sheet, Fortune’s technology newsletter

Amazon unveiled the store concept last December and had hoped to get some locations open in 2017. However, after some of the theft-defying technologies failed, Amazon was forced to work on fixes. A Bloomberg source said that Amazon’s efforts at thwarting thieves have been improving and the company is now looking for construction workers and marketers to help make its concept a reality.

Bloomberg’s sources didn’t say exactly when the stores might open to the public, but testing is ongoing. For instance, Amazon is currently examining how to ensure its technology is sensitive enough to know when someone eats an item in a store. After all, if you eat it, you buy it.