There are many tales told of Ginny Greenteeth, mostly to terrify children (which is no more than the evil little creatures deserve.)

She lives among the weeds with mud between her toes and slime in her hair. She sings to the rats. She talks with the crows and whispers secrets to wriggling little creatures too small to see.

Perhaps she was invented to frighten children from the canal. But a child frightened of mud between their toes and slime in their hair is no child at all. The grown-ups may have invented her but they only managed to frighten themselves.