Piranha locusts were hornet-like insects of the planet Bliss. They were several times larger than normal. They were a dangerous flesh-eating insect species. A swarm of Piranha locusts kills many people on the forests and encountered the Seventh Doctor, Ace and Hex. The DNA of the insects was combined to that of the Silkworms by Professor Toshio Shimura to create a metal-eating parasites called the kiseibya. (AUDIO: Enemy of the Daleks)