On Terrient Tillmorrow, in the Seekmutt account, Acid Fog is listed as a cleric spell cantrip. I haven't tried to cast it or anything, but it's there. I've tried relogging, and it didn't go away, either.

This is a well documented domain bug. You need to redownload the domains .2da I think.

Ignore it. Cast it and the DM's will wtf pwn you.

You cannot cast it, use the search function.

I had this once. (Did I report it? Woops...)

Do you have any items equipped that allow you to use Acidbomb? "Fishing Belt" or something?