Like, the description just says that it’s liquid you can find in the Dark Sea. We have no idea why you get poisoned when you get in, but it can be used to brew burning potions (just what). Also it seems that liquid starlight pools tend to be bigger the further you go, so it’s probably linked to mag…

I got Mis to ask tech what it is one time Tech said it is liquid mercury Explains the poison, but why does it burn?