hit the fan

Uncertain. Possibly derived from an old joke: A man in a crowded bar needed to defecate but couldn't find a bathroom, so he went upstairs and used a hole in the floor. Returning, he found everyone had gone except the bartender, who was cowering behind the bar. When the man asked what had happened, the bartender replied, 'Where were you when the shit hit the fan?' Other possible sources include American/Canadian military slang or agricultural manure spreaders.

• "They were just clowning around, when suddenly it all hit the fan."
• "Then the shit really hit the fan."
• "Let me ask you, Congressman, the case of a lot of these corporate scandals, I followed enough of them to know how -- how it works out. Once everything starts hitting the fan, the CEO, the chairman or maybe a large share of the board of directors simply leaves, resigns"

• shit show
• shitstorm
• shower of shit
• shit happens
• shit rolls downhill