What is the marine etymology of "torpedo" which now names an underwater missile?

The name derives from the Latin word torpere, which means to paralyze and cripple.

The word torpedo comes from the name of a genus of electric rays in the order Torpediniformes, which in turn comes from the Latin torpere ("to be stiff or numb"). In naval usage, the American Robert Fulton introduced the name to refer to a towed gunpowder charge used by his French submarine Nautilus (first tested in 1800) to demonstrate that it could sink warships.