TV-Series
Description
Rocky Hammerhead began as a prehistoric caveman, a tall and muscular figure clad in grey or purple fur clothing with arm wrappings and a rope belt. He wielded a spear, his eyes unseen. He lived a physically demanding life, hunting dinosaurs such as Triceratops alongside his son, Flint.

This era concluded when Rocky and Flint were fossilized by Petra Fina during her pursuit of the Time Shifter Getalong. The fossilization happened amid a volcanic eruption; evidence implies Rocky may have activated Petra's fossil gun himself to shield Flint and Getalong from encroaching lava. They remained fossils for millions of years until their discovery in the 25th century.

Defossilization by Dr. Bernard Goodman left Rocky incompletely restored due to gaps in the fossil record. He emerged as a sentient, flat rectangular stone slab possessing visible eyes but no other facial features. Dr. Goodman subsequently fashioned this stone form into a functional axe, becoming Flint's primary weapon. This axe form features a red light on the head and a handle with two buttons.

As a sentient axe, Rocky retains his full personality and memories, though fossilization erased some recollections, including those of his wife (Flint's mother). He remains protective and supportive of Flint, offering guidance during missions and emotional comfort. Rocky adapts more readily than Flint to 25th-century life, displaying a generally laid-back demeanor tempered by stern discipline when needed. He also shows occasional susceptibility to flattery, particularly when interacting with Petra Fina disguised as Ms. Iknow.

Rocky's axe form possesses specific abilities: emitting a beam that fossilizes or defossilizes non-evil entities, and dramatically increasing size through focused "fighting spirit," reverting if concentration wavers. This growth ability features in both the anime and Bros. Comics manga, but not in Bom Bom Comics. His bond with Flint allows him to occasionally resist mind-control, such as breaking Petra Fina's P-Stamp influence.

Across all media, Rocky serves as both weapon and mentor. In Bom Bom Comics manga, his protective nature extends to physically disciplining Flint, Sarah, and Tony when warranted. A notable story arc involves his near-marriage to Ms. Iknow (Petra Fina), stemming from her manipulation and his susceptibility to her flirtation; however, he prioritized rescuing Flint over continuing the relationship.