It's a phone accessory fit for the creepy Queen St Santa.
Researchers in France have created a robotic finger that can carry out actions like waving, stroking, crawling and - of course - beckoning.
"In the spirit of human augmentation, which aims at overcoming human body limitations by using robotic devices, our approach aims at overcoming mobile device limitations (static, passive, motionless) by using a robotic limb," Marc Teyssier, one of the MobiLimb's creators, wrote on his website.
"The users can manipulate and deform the robotic device, they can see and feel it - including when its shape is dynamically modified by the mobile device, [and] as a robotic manipulator, it can support additional modular elements (LED, shells, proximity sensors)."
If it's not creepy enough already, there's also a human skin-like glove that puts the MobiLimb right into uncanny valley territory.
"Using a humanlike skin with the phone illustrates changes the perception of the mobile device from an inanimate object to an 'almost' human entity," wrote Mr Teyssier, a PhD student at la Sorbonne and Télécom ParisTech.
When magazine New Scientist shared video of the MobiLimb on Twitter, the response was a mix of horror and lewd jokes.
"If my phone did that, I'd hit it with a broom and bury it with a stake through its heart and a really big rock on top. And even then I'd not sleep soundly," wrote @slrellison.
"This will be terribly misused," said @DJmaroto.
"I would never pick my phone up again if it could tickle me," said @ac00perw.
"There's definitely an unsettling, creepy way in how it moves," tech journalist Dami Lee wrote for The Verge. "Maybe it's the way it drags its lifeless phone-body across the table to let you know you have a new message. Or maybe it's the human flesh cover for the finger that turns it into a dismembered digit?"