Funny, I heard someone talking about their last ghost being in Grimssea Bottom just today :)

Do those appear randomly?

Nice shot! I miss the ghost quest. I had fun with that one.

The ghosts appear in certain spots on the map for a quest: "Notice the Unnoticeable" you can see which locations they appear at on this page [Spoiler Alert!]: www.glitch-strategy.com/wik...