A few days ago I checked back on a Jool probe I had launched a few months (IRL) prior. I decided to go get some Science from space near Laythe, since this probe wasn't designed with landings in mind. Anyways, after a 600-ish m/s correction burn I was set for Laythe.
I never checked my periapsis on the Laythe flyby.
It was 41km, 9km into the atmosphere.
By the time I realized, it was too late and I never quicksaved. The probe crashed into the seas of Laythe.