Grogg

Grogg is an alien in the Generation 1 continuity family.

What have I got in my pocket?

Grogg has guarded the library planet of Andellor and the Power Prism for a millennium.

Fiction

Blackthorne Publishing continuity

To retrieve the Power Prism, an invader has to survive chambers full of worm creatures and answer Grogg's riddle:

"It cannot be touched, tasted, seen, or heard; it might not exist at all, except that its strength has laid low the greatest titans. All live under its reign, and eventually fleshling, Autobot, and Decepticon will all fall before its just hand. What is this?" Transformers in 3-D issue 2

Well, at least the worm creatures are tough.