He and many members of the Lemons attended a meeting, so they could all discuss on how to discredit Allinol. The Lemons were using the electric pulse generator that looked like a camera to make the racers blow their engines and crash. This would ensure that all the cars would keep using convention fuel to secure the profits of the whole Lemon organization. He liked this idea, and he mentioned that he's from Detroit, Michigan when Victor Hugo entered the meeting room in Italy.
After Professor Zündapp faced his defeat, J. Curby and many more members of the lemons showed up. When everyone was fighting, Red showed up and successfully sprayed J. Curby and some of the members with his hose, leaving the terrorist trapped at the fence near one of the buildings in London, the location where he was arrested.
Like all the other Lemons, J. Curby Gremlin is a cold-hearted terrorist who would do anything for a quick buck. He is also notorious for being a crime boss and an iron-fisted family leader.
Apparently, he is very sadistic because he loved the idea of discrediting Allinol by using the electromagnetic pulse generator disguised as a camera which would cause the racers to blow their engines, crash, and make sure that every car would keep on using ordinary fuel to secure the profits of the Lemon organization.
He is a 1974 AMC Gremlin with a purple paint coat and the yellow hockey stripe.
His license plate number is RB 214
J. Curby is the only head lemon who was seen with a weapon.
According to the French version of Cars 2, J. Curby's full name is John Curby Gremlin.