Agatha

Agatha is a character mentioned in the book, How to Train Your Dragon  of the Book series.

Borrowed Dress
As the Hairy Hooligan Tribe and the Meathead Tribe started dealing with the arrival of the Green Death on the shores of Long Beach, 400 Vikings yelled at the colossal Dragon to Go Away. The Green Death roared back, then sliced the clothing off Gobber the Belch and flicked him back to Hooligan Village. He went through the grass roof of his own house and fell into a chair, naked. The only thing in his home to put on was his Cousin Agatha's apron dress. This implies that extended families may live together under one roof.

Physical Appearance
Agatha is not seen or described in the Book series. However, Gobber is depicted wearing her dress. Agatha must be a tall, thick woman for Gobber to be able to fit in her dress.