Scalp

Scalp is a Transformer from the IDW portion of the Generation 1 continuity family.

You can't see me!

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

Scalp transforms into a big head, appropriately enough.

Fiction

IDW Generation 1 continuity

Tailgate, who was friends with Scalp six million years ago, brought him up while talking about Chromedome, Brainstorm and Highbrow's head-themed names. The Reluctant Specialist