So I've got this superpowered mutant superweapon created by some metallic race. It was meant to devour life on worlds in order to clear out areas for colonization, but stuff went wrong and it escaped and regained sentience and decided it would rather go on adventures and make friends(it still has to eat a lot to sustain its high energy needs enough so it won't revert into an uncontrollable ravenous monster). It goes into a hibernation state when traveling between solar systems.
At first I decided it would use energy derived from animal life(or high energy foods because it doesn't want to be a murderous superweapon) to convert to matter to repair itself(it's made of elements from a neighboring universe so using the elements found in the home universe wouldn't work). Then I found out that it takes an absolute heck ton of energy to make matter.
So unless I can figure out how converting normal energy into some magical energy(magic does exist in this universe) and then the magic energy into larger amounts of matter than regular energy-to-matter conversion would get you might work(anyone with ideas let me know; I'd rather something like this actually), it would need to be able to convert matter into energy and then into usable elements.
But then how could it be prevented from consuming entire planets into its pocket dimension stomach if it wanted to? It would store energy in pocket dimension containing micro crystals throughout it's body.
Maybe a solution would be that it can transfer organic matter into energy easier than inorganic matter? But then why and how would that work?