- Type: Yacht
- Displacement: 9,923 tons
- Dimensions: 414 x 69 x 18.5 ft.
- Machinery: 8 diesels, 2 shafts, 19,200 bhp = 20 knots
- Crew: 57
- Passengers: 26
- Builder: Lürssen, Bremen, Germany, 2003
- Service: Built for Microsoft co-founder Paul Allen. Octopus sports two helicopter pads on the top deck, a twin pad and hangars at the stern and a single pad on the bow; and a 63-ft tender docked in the transom. There are a total of seven tenders aboard. The yacht also has a pool, located aft on one of its upper decks, and two submarines (one of them operated by remote control for studying the bottom of the ocean). Side hatches at the water line form a dock for jet skis. The exterior was designed by Espen Øino Naval Architects and built by the German shipbuilders Lürisen in Bremen and HDW in Kiel. The interior was by designer Jonathan Quinn Barnett of Seattle.
Allen has loaned Octopus for a variety of rescue and research operations, including an attempt by the Royal Navy to recover the ship's bell of HMS Hood, sunk in the Denmark Strait in 1941. At 9,000 ft down, the bell was located in 2012, and eventually recovered in 2015. An Allen-led research team also announced the discovery in 2015 of the wreck of the Japanese battleship Musashi, sunk in the Sibuyan Sea in the central Philippines in 1944.