Is there a potion or elixir to make a Galactic Zentu? I would like to have one, and have no idea how to make one. (All my slots are filled, I would use one of my non-Zentu pets to make the Galactic Zentu.)

If you got to Coda Caves on Atebus you'll find a link to Iltallo who will allow you to change your pet to Galactic in exchange for some Coda Cave crystals. You should be able to buy the crystals from user shops if you don't have them.

Thanks!

You'd have to use a different Zentu elixir first if your pet isn't already a Zentu, like

You can buy them at Five Seven Five