Not really true.
Matter and Energy are intertwined according to Einstein and verified by experimental data. The old E = mc squared thing. Matter can be converted to pure energy, and vice versa. The fact that we’re all here is pretty good physical data that matter can be created!
I suppose an alien race could have figured out how to operate in the 4th dimension and have the ability to make things appear to “disappear “ from 3 dimensional space. They would have to be some pretty cleaver bee keepers indeed.