He was remarkable for ugliness, and was an object of aversion to his parents.
In this he is described as a monster of ugliness and deformity, as he is also represented in a well-known marble figure in the Villa Albani at Rome.
His extreme ugliness in later life is attributed to an attack of typhus, from which he suffered in 1771.
Its ugliness was emphasized by the old felt hat which he wore, - its sole ornament the leaden figure of a saint.
He at once began love-making, and in spite of his ugliness succeeded in winning the heart of the lady to whom his colonel was attached; this led to such scandal that his father obtained a lettre de cachet, and the young scapegrace was imprisoned in the isle of Re.
They waged war against him as relentlessly as did the Constitutionalists against Mirabeau, whom he resembled in his extreme ugliness and his volcanic eloquence.
Giovanni the Lame (Sciancato), a man of a daring impetuosity only equalled by his ugliness, had proved so useful a general to Giovanni da Polenta of Ravenna as to win in reward the hand of that potentate's beautiful daughter, known to history as Francesca da Rimini.
In February 1792 an allusion in debate by Toler (afterwards earl of Norbury), the attorney-general, to Tandy's personal ugliness, provoked him into sending a challenge; this was treated by the House of Commons as a breach of privilege, and a Speaker's warrant was issued for his arrest, which however he managed to elude till its validity expired on the prorogation of parliament.