They say you give up a few things, chasing a dream. In those mists that's the literal truth, for every dream of yours that comes true, a piece of yourself, mind, body, or soul, gets taken by the mist. Worst part is, you won't even know what the cost of your dreams are until you go to leave, and by then you might not even have a mind left to change...
A fragment of the mists of creation, drawn to those desperate to make their dreams come true. Suitable for any magical fantasy setting.
During big fights in the arena or gladitorial ring between two well known or important warriors. When one looses and dies, the crowd throws copper coins into the arena for the slain warrior to take with them on their passage of death. This is to make their passage and afterlife richer and less troubled. It is a sign of respect.