Black Annis is a character from the local village legends of central England, a cannibal hag with a blue face and iron claws supposed to live in a cave in the Dane Hills in Leicestershire. There was a great oak at the mouth of the cave in which she was said to hide to leap out, catch and devour stray children and lambs. The cave, which was called "Black Annis' Bower Close", was supposed to have been dug out of the rock by her own nails.

On Easter Monday it was the custom from early times to hold a drag hunt from Annis' Bower to the Mayor of Leicester's house. The bait dragged was a dead cat drenched in aniseed. Black Annis was associated with a monstrous cat. This custom died out at the end of the 18th century. Black Annis and gentle Annie are supposed to derive from Anu, or Danu, a Celtic mother goddess. Donald A. Mackenzie suggests a connection with the Irish Aine, the mother of Earl Fitzgerald. The Leicester Chronicle of 1842 mentions a tomb in Swithland Church to Agnes Scott, an anchoress, and suggests that she was the original of Black Annis. Ruth Tongue in her Forgotten Folk-Tales of the English Counties reproduces a tale about Black Annis the hag. It was told by an evacuee from Leicester in December 1941. Her description seems to show that the tradition of Black Annis was still alive just over thirty years ago:

Black Annis lived in the Danehills.

She was ever so tall and had a blue face and had long white teeth and she ate people. She only went out when it was dark.

My mum says, when she ground her teeth people could hear her in time to bolt their doors and keep well away from the window. That's why we don't have a lot of big windows in Leicestershire cottages, she can't only get an arm inside.

My mum says that's why we have the fire and chimney in a corner.

The fire used to be on the earth floor once and people slept all round it until Black Annis grabbed the babies out of the window. There wasn't any glass in that time.

When Black Annis howled you could hear her five miles away and then even the poor folk in the huts fastened skins across the window and put witch-herbs above it to keep her away safe (1157).

A full account of the various traditions about Black Annis is given by C.J.Billson in County Folk-Lore (Vol.I). It has been suggested that she is Milton's "blew meager hag" (1290: pp.24-25).

In 1999, J.K.Rowling, especially for the Harry Potter fan club, published a number of notes from the Daily Prophet, the newspaper of the wizarding world, among which was a letter from Black Annis:

"I am deeply hurt at your false and vicious assertion that I am nothing but a flesh-eating monster."

She wrote a letter to the Daily Prophet complaining about the paper's portrayal of Hags as flesh-eating monsters. Her letter stated that her own interests included poetry, crochet and gardening. She also offered baby-sitting services.