Leonardo da Vinci designed a scythed chariot with a rotating blade mounted on a shield-like body.
His military drawings include a cart fitted with long blades that would rotate as the vehicle moved. The design was intended to cut through groups of opposing soldiers and create terror on the battlefield. It combined a wheeled platform with a mechanical transmission that transferred motion to the blades.
The idea belongs to a much older weapons tradition. Scythed chariots were used in the ancient world, especially by Persian armies, where blades were attached to chariot wheels or axles. Leonardo's version reworked that concept with Renaissance mechanical details rather than inventing the basic idea from nothing.
No evidence shows that Leonardo's chariot was built or used in combat. Like many of his military inventions, it is best understood as an engineering proposal designed to demonstrate ingenuity to powerful patrons.