In “Kingdom of the Crystal Skull,” Shia LaBeouf plays Mutt Williams.
Mutt is introduced as a motorcycle-riding American greaser who asks Indiana Jones to help find the missing scholar Harold “Ox” Oxley. Their search leads from the United States to Peru and the mysterious crystal skull.
Mutt’s connection to Indiana Jones becomes one of the film’s central revelations: he is Indy’s son with Marion Ravenwood. His birth name is Henry Walton Jones III, but he uses his stepfather’s surname, Williams, and is generally known as Mutt. That makes “Henry Jones III” a tempting but less appropriate answer to this question.
The character was designed as a rebellious 1950s counterpart to the younger Indiana Jones. LaBeouf prepared by studying greaser films such as “The Wild One” and “Rebel Without a Cause.” Although Mutt was positioned as a possible successor to Indy, the later film “Dial of Destiny” establishes that he died while serving in the Vietnam War.