In the mid-1500s Vienna was plagued by regular summer infestations of lobsters which caused significant damage to local buildings and livestock. In '57 the Mayor, Hans Übermann, commissioned Lazansky von Bukowa (Great^5 grandfather of Joseph Haydn) to come up with a solution and the famous Viennese polymath did not disappoint, designing and building a 15 foot long coal powered shark made entirely of brass.
Sadly, 15th century control systems were not of a sophisticated type, and shortly after launch the shark went haywire, attacking shipping in the Danube and causing severe losses to the merchant fleet. The shark could not be caught using conventional nets, which it bit through, and a harpoon squadron bought in by the mayor failed the make any impression on its brass hide. von Bukowa had fled to a monastery in disgrace, but returned to the city in the autumn when the mayor begged him to find a way to capture or destroy his creation.
By coating a large fishing net with a viscous mixture of honey and candle-wax, von Bukowa was able to produce a trap sticky enough to trap his mechanical selachimorpha and was able to dismantle it on the deck of the vessel Pride of Urbino. He received 12 shillings for his efforts, though never the freedom of the city (which many believe was denied to him by a furious Guildhall, many of the Members of which has suffered damages from attack by the shark)
Curiously enough, the lobsters never again threatened Vienna, probably because the mechanical fish had caused them to flee for safer waters.