From the pics, it doesn't appear that there are any "breaks" on the bushing. That is, when installed, the bushing sat concentrically onto some type of suspension component.
With no fracture point visible on the bushing, it would be impossible for it to come off unless the shaft it was riding on gave out.
So either you have a catastrophic failure on your hands, or the bushing came off another vehicle...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car