What Earth element is energon?

If you want the SERIOUS answer, it would almost certainly have to be either uranium or thorium. But TBH I like Lujk's answer more. You know, it's like dilithium in star trek or naqueda or naquadria in stargate. Or dragonite in Outlaw Star. Or upsydaisyium in Rocky and Bullwinkle. Or unobtanium in The Core. Or oryhalcyon in all sorts of swords and sorcery universes. It's made up garbage. The sad thing is that there is nothing new that can ever be discovered and put on the periodic table that lasts geological periods of time, the only elements not already on the periodic table would be gone in the blink of an eye, the era of mystery and discovery in chemistry like that is long gone. You know, just like you can make new sci-fi about journeys to Venus but now that we know it's a very hot, sulfuric acid covered planet with no life, the mystery and wonder of the golden age sci-fi from before that was known can never really exist again, in the back of your mind, you the viewer will know it's all BS.

Energon is henryfordium