What planet pounder is most potent?

I’m convinced DalekTek790 has proven for us who Mantrid is now
Who is the Doctor

The Doomsday Machine in the original Star Trek was a planet eater and because it defeated a Starship captain without even being commanded it was at least a minor contender, imagine what it might have done under intelligent control? Neutronium hull! Beat that. How powerful would Lexx be without a Captain. I think I’ve only seen it blast something without orders once (series 1).