Freddie As F.R.O.7. (1992)

He's a secret agent with secret powers. A leaping green fighting machine defending the world against the forces of evil.

Frederick is a young medieval French prince with magical powers, turned into a frog by his evil sorceress aunt, who kills his father in a bid to seize the throne. After being pursued by his aunt, the prince is saved by the Loch Ness Monster, who indebts herself to him, and hides out with a colony of anthropomorphic frogs for a time. After ultimately deciding to accept his fate and fight evil using his powers, Freddie grows to the size of an adult human, travels to the future, and becomes a French secret agent with a sentient car.