the only thing I have is euphorbia glitz. I haven't seen that for sale in any seed catalog. If you want a glitz plant I can send you that, but it isn't anywhere close to what you are looking for. It has a cloud if tiny white flowers and is used as a filler in pots. Can you go back to where you saw the plant and get a cutting and root it?
Donna, it's an amaranth. Both Burpee and Parks have seeds. I can't recommend either, but if those are the only alternatives . . . . Take a look at their on-line catalogs and see if that is what you want.