Eugene Mulchandani was a foreign exchange student from Gorakhpur, India. He went to the Longborough School for Boys with Ned. He was the only lab partner left after everyone else chose theirs. Eugene had a great interest in flight, and his paper airplanes were more complex than usual. Ned saved him from being bullied by another student, after which he and Ned became friends. Eugene saw Ned touch dead leaves which then turned green and was a little shocked at this.
Eugene wore highly visible orthodontic headgear, part of what made him a target for bullies, although there were seemingly numerous elements to that.