What’s the worst amount of body damage/bondo you discovered after you bought the car??

In the late 80's, I bought a '63 Dodge 330. Slant six, automatic, 4 door. Plain jane bottom feeder B body. Bought it cheap and it had a bit of typical rust around the headlights, but really didn't look all that bad. It was cheap... I bought it to use as a general driver, mostly back and forth to work. It was just rusty enough not to do anything else with but drive it.

All was good until I got it home... I had two small boys, so seat belts for the car seats were needed and just a good idea anyway... I pulled the back seat and all was good and then pulled up the rubber floor mat... Yea, rubber floor mat. The floor had looked pretty good from underneath, with the exception of a hole about 6" square under the driver's feet. With the mat out... The floor was paper thin everywhere and no way was there going to be good anchors for front belts without major work. I could just envision the front seat falling through the floor once a couple adults sat on it.

I ended up running some steel bracing across where front belts bolted and then got out the fiberglass cloth and resin and 'glassed in the entire floor of the car with 2 layers. A friend gave me a carpet from a '72 Satellite that fit well enough to cover it up and I drove that car for several years after that.

Funny story... I was standing in the driveway watching my son walk up and as he walked past the Dodge, one of the torsion bars snapped. The car lurched over and dropped, and he jumped. He looked at me and said "I didn't do it!".