The Jacobite toast to 'the little gentleman in the black velvet waistcoat' was to what small animal, held responsible for the death of William III?

William III (4 November 1650 – 8 March 1702), also widely known as William of Orange, was sovereign Prince of Orange from birth, Stadtholder of Holland, Zeeland, Utrecht, Gelderland, and Overijssel in the Dutch Republic from 1672. He was also King of England, Ireland, and Scotland from 1689 until his death. It is a coincidence that his regnal number (III) was the same for both Orange and England. As King of Scotland, he is known as William II.

In 1702, William died of pneumonia, a complication from a broken collarbone following a fall from his horse, Sorrel. The horse had been confiscated from Sir John Fenwick, one of the Jacobites who had conspired against William. Because his horse had stumbled into a mole's burrow, many Jacobites toasted "the little gentleman in the black velvet waistcoat." Years later, Winston Churchill, in his A History of the English-Speaking Peoples, stated that the fall "opened the door to a troop of lurking foes". William was buried in Westminster Abbey alongside his wife. His sister-in-law, Anne, became queen regnant of England, Scotland and Ireland.