ADO.NET documentation shows the possibility of setting the transaction level for a SQL transaction to Chaos. It sounds unpleasant, but if the feature is there, presumably it has some legitimate use.
The SET TRANSACTION ISOLATION LEVEL command in BOL (ah! see, I can use google and BOL) nothing seems to be named "chaos" and ADO.NET does have 5 modes that match up nicely to documented levels in addition to "chaos"
What or who is this Chaos level for? (And why does it have an unfriendly name?)
Refs: The ADO.NET enum