Years ago the apartment complex I was living in was getting renovated. We got these little caravans put up out in the back which we could use as kitchens and bathrooms as ours were getting renovated. The bathroom ones had pump issues, and one day, as I was preparing to get into the shower in this freezing cold caravan (because what better time to do this than in the middle of the winter?), the pump crapped out and the sewage ended up backflowing, regurgitated out of the shower drain.