1) When someone takes a dump on a toilet where someone had previously died elvis presley style and feels that person's spirit dump with them.
2) A spirit that watches you whilst you take a dump. In other cultures, the spirit dump may also try to capture you while you are in the middle of dumping.
1) "Ah man, that dump I just took felt weird...like someone else was taking a dump with me." "Dude you probably just had a spirit dump."
2) "Nick went into the bathroom and now he's gone!" "Maybe the spirit dump got him."