He is the patriarch of the Boom Boom Family and father of L. A. and Andre. Benjamin Boom Boom is one of the racers of the Steel Ball Run and attacks Johnny Joestar and Gyro Zeppeli to eliminate competitors.
Benjamin appears like a big middle-aged man in his late forties. His most peculiar feature is the metallic apparatus covering the bottom of his face, which he can sink inside his face to change facial features. He wears a dotted cowled, hooded cloak and an iron mask that covers his jaw.
Benjamin is a murderous and greedy man, who targets other competitors in the Steel Ball Run to get ahead and obtain the prize money.
Benjamin is very aggressive, constantly shouting at his sons (especially L.A.) and badmouthing his wife. Although he protects his sons using his Stand as a shield, he pays no mind to the agonizing Andre and leaves him alone. He seems to hate the mother of his children, who supposedly abandoned the family to "be a whore".
- Main article: Tomb of the Boom 1
Tomb of the Boom grants every member of the family the ability to manipulate iron different ways. Benjamin manipulates pieces of iron by putting them under his skin, allowing him to change the appearance and hide weapons.
After his son, Andre, tricks Gyro Zeppeli and Johnny Joestar and manages to transform the first into a human magnet, Benjamin and L.A. attack them unsuccessfully. Benjamin, however, manages to exploit Andre's power in a diabolic way: by shooting at him, he manages to drop some of his son's blood on Johnny, therefore turning him into a magnet as well.
By assuming Johnny's identity, he manages to magnetize Mountain Tim too: his plan is to make the three of them approach and be killed by the magnetic power of the Boom Boom family. However, it fails when Mountain Tim uses his Oh! Lonesome Me to tie himself to a rock. Forced into close combat, he ultimately manages to make his three enemies gather, but Johnny develops Tusk at the last moment and cuts him in half.
Chapters in order of appearance