Invisible telephone

You can't see me!

_{This character has no official visual representation in any Transformers product or media... yet, at least.}

The invisible telephone is just like a regular telephone but invisible! Doc Greene keeps it in the Hall of Inspiration's "Best Left Forgotten" room with other stuff like the perpetual motion lamp and the weather machine.

Fiction

Rescue Bots cartoon

While taking Frankie and Cody to find the weather machine, Doc Greene joked that the invisible phone was missing. He wasn't all that sure that the telephone was actually there though. Christmas in July