“ On a planet with an ammonia atmosphere, that is inhabited by intelligent aliens, the police carry oxygen spray, that has the same effect on that planet that pepper spray does here.”
“ Mining in a certain area turns all exposed skin (maybe just parts that are actively disturbing the chemicals that cause the reaction) of the those doing the mining to a dark blue color. Will wear off taking as many years/days spent in the mine. ... meeting a party of blue-skinned humans armed with pick-axes etc. Strange disease? Demon offspring? Curse? If they meet only one ex-worker, they will very carefully listen to any stories he says, no matter if drunken or insane, or just makes up to get a beer.”
“ He's a non-descript man, with his pushcart. On it he sells nothing more exotic than jars of sun-dried tomatoes in oil and pickled vegetables. But he's always out there, in the courtyard of the great Guild of Wizards, in most weathers, and he'll have a kind word for you, and a jar.”