What could have caused this to my wheel?

2001 3.4L Tacoma

Heard a clanking noise on my back left tire one day and all of a sudden three lug nuts were missing and every whole around each stud is ground down. I added a few extra lug nuts I had but if you can’t tell in the pictures the metal on the wheel looks like it ground all the way through.

what could have caused this?

 

Lug nuts look loose or broken. Also, clean that rim up. Welcome to TW.

 

Loose nuts. Wheel wallowed out on the nuts/studs. Amazing you didn't feel it.

 

I was off roading when it happened but no I didn’t hear or feel it till later.
So I need a new wheel nothing else?

 

Welcome to TW...new wheel and check all your studs for damage.