Eddie is mean, evil, ruthless, selfish, sadistic and bratty. He believes he is a lot smarter than Jimmy (which is somewhat accurate since he is a baby). When there are adults around, just when he talks in his normal voice, he then suddenly talks in a baby voice and says, "Goo", feigning innocence. He was plotting to do away with the entire clan so he could get Great-Aunt Amanda's inheritance.
Despite his intelligence and adult voice, he is still as mentally immature as he is physically. He cries when he is upset, he threw a fit when Jimmy destroyed his rattle, demands his cup, and always demands a diaper change from peers and others. He always smells and has a full diaper on.
- Eddie's attitude and behavior is quite similar to Chucky from the Child’s Play franchise.
- Since he is trapped in the dinosaur times, it is most likely that he was either eaten by one of the dinosaurs or has managed to scare them off with a 5 day old poopy diaper.
- He flirted with Beautiful Gorgeous in "The League of Villains," but she never returned the feelings.
- Eddie is similar in terms of behavior to Stewie Griffin from Family Guy as both are evil, are a year old, and have the ability to talk and walk.
- He resembles Granny Neutron as an infant, as seen in "Granny Baby".
- Eddie is the only villain to be related to any of the main characters.
- After finding out Eddie was evil, Great-Aunt Amanda calls him “a bad seed”.
Villains: King Goobot V | Professor Calamitous | Eustace Strych | Beautiful Gorgeous | Meldar Prime | Evil Jimmy | The Junkman | Zix, Travoltron and Tee | Baby Eddie | Gortox the Irritable | Dr. Sydney Moist