Parasite

The, called Parasite Chrysalis in the English dub of the anime, are demons who posses other demons to protect themselves. Naraku uses Parasite Chrysalis to steal Fuyoheki from Gakusanjin, and then order to Kagura and Kohaku to exterminate them.

Sango knows very well the Parasite Chrysalis, and seeing the multitude of corpses in a pond, she understand that they have taken possession of a gigantic demon.

宿蛹