Ya, it's ugly. I know a merge is not reversible. Monday night, one of my users somehow merged 167 customers into their "parent" company (it's the partner in real life, but it's set up as the parent in NS). She doesn't know how she did it.

With these customers came all their Contacts, opportunities, sales orders, support cases, custom records that track what they own, and on and on. Some of them had login access to the Customer Center so, temporarily, they could log in and see whatever info is available in the Customer Center for all of the 166 other customers (cases, primarily).