So it seems that it was applied to the electric ray, because touching it makes you numb. And then transferred to underwater projectiles because they reminded people of the fish!
Well, although they are a water-borne missile they do sometimes jump out and hit something while in the air. They can be launched from outside the water as well, and have probably been known to explode then; but that probably isn't what you mean though as it would be by accident, not design.
Something similar is the Exocet, a type of missile that is named after a flying fish.
Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.
