Jimmy Negatron is an evil version of Jimmy Neutron from another dimension. He only appears in the video game titled "Jimmy Neutron vs. Jimmy Negatron." He is similar to Evil Jimmy, one of Jimmy's clones.
Negatron looks just like Jimmy, except he has a goatee and wears a mad scientist outfit.
- Negatron's goatee may have been inspired by the Star Trek episode titled Mirror Mirror, in which the evil version of Mr. Spock has a goatee
- The goatee might also be a reference to the Codename: Kids Next Door episode Operation: P.O.O.L., where Negative Numbuh 4 had a goatee
- Negatron was originally going to be a character on the show and his name was gonna be "Nummie Jetron". That role was given to Evil Jimmy.
- Though it is never confirmed, Negatron's full name is most likely James Issac Negatron.