Ghost:
Event , belief, etc
The belief that the main character had about themself. In the hustle and bustle of daily life, doesn’t take time for themself to feel things, sweeps things under the rug. Maybe before the trip they are fighting with their boyfriend and something happens with their roommates or at work.
Or maybe someone close to them dies and then they are taken on this trip to find peace but instead are forced to be uncomfortable and face things head on.
Each spider falling could be pressuring the main character more and more to feel things and remember things and experience pain and grief in a time where they need to work hard and get through the stream.
Lives day to day life ignoring this grief instead of facing it.