Photons, although mass-less, have energy and can therefore be converted into matter under some circumstances.
Apparently my well intentioned ramblings can be directly converted into brain farts.
What is “stuff” as all matter no energy?
Alternatively, possibly dark matter would qualify, although I am not sure either as we haven't even proven that it exists.
Photons, although mass-less, have energy and can therefore be converted into matter under some circumstances.