Midrash su Ester 9:7

(Esth. 9, 7) And Parshandatha R. Adda, of the city of Japhe, said: "The names of the ten sons of Haman, together with the word Assereth (ten), must be read in one breath." Why so? Because their souls left their bodies all at the same time. R. Jochanan said: 'The [letter] Var of Vai'zatha must be made longer, that it should resemble a gallows, for all ten were hanged on one gallows-tree."