Ratchet Dr.

Dr. Ratchet (ドクター・ラチェット, Dokutā Rachetto), the main antagonist of the seventh movie, is a great inventor who believes that with his natural genius he should rule the world. He is the Feudal Lord of Mecha Island. He tricks the Straw Hat Crew into waking up the island (it is actually a giant turtle, the island is its shell), which he then uses giant cables to force it to move wherever he wants to advance his domination plot. Ratchet and his two henchmen pilot mecha to stop the Straw Hats, but to no avail. When his first mecha is destroyed, Ratchet gets into a gigantic mecha in an attempt to defeat Luffy.

At the last second, Luffy (unknowingly) activated Gear Second and completely obliterated Ratchet's mecha with a Jet Bazooka. For his misdeeds, he ends up being spanked by his mother. (source: onepiece.wikia)