Twin Signal (ツインシグナル, Tsuin Sigunaru) is a manga series written by Sachi Oshimizu.

It follows the story of a humanoid created by a robotics expert named Dr. Otoi for his grandson, Nobuhiko.

But in the process of writing and applying the programming, an unfortunate mishap took place when Nobuhiko sneezed.

Now, whenever Nobuhiko sneezes, the humanoid (named Signal) transforms from a temperamental adult robot into a chocolate-loving baby version of himself.

Dr. Otoi's mysterious rival has packed him to the brim with amazing weaponry, with the intent of stealing the Doctor's most recent technology.