Fantastic Beasts and Where To Find Them
Pickett was a Bowtruckle that was kept by Newt Scamander as a pet. Although he had at least six Bowtruckles (Pickett, but also Titus, Finn, Jeremy, Marlow, and Tom), Newt was especially fond of Pickett, and even carried him around in his top pocket, because Pickett had attachment issues.
Pickett accompanied Newt on his journey to New York, sitting inside his top pocket. He was present when the Niffler escaped and when Newt was taken to the Magical Congress of the United States of America by Porpentina Goldstein.
Later, when Newt met the goblin gangster Gnarlack, Newtagreed to give Pickett to him as part of a deal to obtain information about the last missing beasts. Gnarlak betrayed them and turned them into MACUSA. In the resulting fray, Newt was able to rescue Pickett and escape.