A BBC article reported SmartUp has recently discovered the three-year-old patent, which has been described by the tech firm as "one of Google’s creepiest" yet.
The report pointedly plays up the spying connotations of toys listening to kids.
In the patent document, Richard Wayne DeVaul, Google director of rapid evaluation and mad science, explained how the toys would include microphones, cameras, speakers and motors. It also included information about the use of a trigger word that would be used to spur a toy into action, causing it to make eye contact with the child playing with it.
The patent stated: "To express curiosity, [it] may tilt its head, furrow its brow, and/or scratch its head with an arm."
Drawings of rabbit and teddybear toys have been used to illustrate the concept. The patent explains the animals would encourage children to interact with the toy.
The device's applications include controlling TVs and other smart devices, such as central heating systems, curtains and lights.
A spokeswoman for Google told the BBC: "We file patent applications on a variety of ideas that our employees come up with.
"Some of those ideas later mature into real products or services, some don't. Prospective product announcements should not necessarily be inferred from our patent applications."
The idea has sparked opposition from various groups, including the Campaign for a Commercial-Free Childhood, which has also taken umbrage at Mattel’s plans for a "Hello Barbie" eavesdropping doll.
This article first appeared on marketingmagazine.co.uk.