Check out the Giant Malaysian Katydid (Macrolyristes corporalis)! This is one of the largest insects in the world, with their bodies growing to 15 cm (6 inches) long with a 25 cm (10 inch) long wingspan. Though the last thing you want to hear is that this giant insect is carnivorous, they pose absolutely no threat to humans (aside from haunting your dreams, of course).
Relatively speaking, the males of this species have the largest testes of any known animal at 14% of their body weight. If humans had the same ratio, a 91 kg (200 lb) man would have testes that weighed nearly 13 kgs (28 lbs)!