Antonio was a baby Chupacabra chained to Gellert Grindelwald's chair in his cell during his brief imprisonment at the Magical Congress of the United States of America in 1926-1927. Most notably, it participated in Gellert Grindelwald's escape.
Shortly before Grindelwald's attempted extradition to Europe, under escort by several Aurors and Rudolph Spielman (the International Confederation of Wizards's Head of Incarceration) Grindelwald managed to switch places with MACUSA official Abernathy using the Polyjuice Potion. After the high-security flying carriage set off from the Woolworth Building, the real Grindelwald Apparated onto the carriage, eliminated all the Aurors, and destroyed Rudolph Spielman's wand, who - panicking - opened the box that had been handed to him supposedly containing Grindelwald's wand, only to have Antonio jump up from inside the opened box and sink his fangs deep into Spielman’s neck.
Once Grindelwald clambered inside the carriage, he grabbed Antonio from Spielman and rubbed him affectionately; but suddenly, Grindelwald looked at Antonio with distaste and judged the Chupacabra to be "so needy", throwing him out the door of the flying carriage. It is unknown if Antonio managed to survive the fall or not.
- Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay (First appearance)
- Fantastic Beasts: The Crimes of Grindelwald