Sources : Torpedo
Pliny the Elder [1st century CE] (Natural History, Book 9, 67): The torpedo knows her power, and does not herself possess the torpor she inflicts; she hides by plunging into the mud, and snaps up any fish that have received a shock while swimming carelessly above her. No tender morsel is preferred to the liver of this fish. - [Rackham translation]
Aelianus [170-230 CE] (On the Characteristics of Animals, Book 1, 36): The fish known as torpedo produces the effect implied in its name on whatever it touches and makes it "torpid"' or numb. - [Scholfield translation]
Isidore of Seville [7th century CE] (Etymologies, Book 12, 6:45): The torpedo is named because it makes the body become numb [] if anyone touches it while it is alive. Its force is such that even the aura of its body weakens the limbs. - [Barney, Lewis, et. al. translation]
Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Fish 7.84): The torpedo also knows its own power, and does not numb itself, as Pliny says; for it hides itself submerged in the silt, and fish which have been stunned by floating over, it suddenly attacks and eats. Nothing is preferred over the tenderness of its liver. Even at a great distance or if a spear or rod touches a torpedo, the person's arms, though very strong, are suddenly stunned and numb, and although he is the swiftest runner, his feet are immediately bound by the touch. But its power is so great that even a breeze from its body poisons the human body. Pliny and Isidore say this about the torpedo. - [Badke translation/paraphrase]