12. 1998 Florida Marlins
After claiming victory in the 1997 World Series, the Marlins traded away a whole mess of stars, including Gary Sheffield, Moises Alou, and Kevin Brown. Then, not two months into the 1998 season, they shipped off Bobby Bonilla (pictured). The result was a 54-108 team with a 5.18 ERA, worst in the NL, and a .373 slugging percentage, worst in baseball.