What is "guivre"

A guivre is a mythical creature similar to a dragon. In legend they were portrayed as serpentine creatures who possessed venomous breath and prowled the countryside of Medieval France. The words "guivre" ( wurm, wyvern (which is derived from it), or serpent) and "givre" are spelling variations of the more common word "vouivre". Vouivre, in Franc-Comtois, is the equivalent of the old French word "guivre." All these forms are derived ultimately from Latin vīpera, as is English viper.