“… A further legend relates that Martha then went to Tarascon, France, where a monster, the Tarasque, was a constant threat to the population. The Golden Legend describes it as a beast from Galicia; a great dragon, half beast and half fish, greater than an ox, longer than an horse, having teeth sharp as a sword, and horned on either side, head like a lion, tail like a serpent, that dwelt in a certain wood between Arles and Avignon. Holding a cross in her hand, Martha sprinkled the beast with holy water. Placing her sash around its neck, she led the tamed dragon through the village.”
From the Wikipedia article on St. Martha, linked here.