I was working for a webhosting company, and someone asked me to rush a change just before leaving. Instead of updating 1500 A records, I updated about 50k. Someone senior managed to turn off the cron though, so what I actually lost was the delta of changes between last backup and my SQL.
I was in the room for this though: https://www.theregister.com/2008/08/28/flexiscale_outage/