Eustace Strych is an rich, tall, snobby, sadistic and petty 11-year-old boy and Jimmy's arch-enemy who talks with a British accent. He also has a disturbing laugh. He is known to be the richest person in Retroville.
Eustace appears in "Billion Dollar Boy," "King of Mars," and "The League of Villains," and makes a cameo appearance in "Attack of the Twonkies" but is only seen for a very brief time in a movie theater watching a Jet Fusion movie. His assistant is named Blix. Cindy had a crush on him in "Billion Dollar Boy" but Eustace was just using her to emotionally crush Jimmy and then force him to watch Goddard die.
Eustace wears a red robe (with the letter "E" on it), black pants, and spats.
In Billion Dollar Boy, Eustace lost to Jimmy in a battle kite tournament and pretended to invite him and his friends to his house. Cindy had a crush on him, but she let it go when she realized that Eustace is a petty, sadistic jerk and was only using her to hurt Jimmy. At his house, Eustace challenged Goddard with his Robot-Adaptoid and nearly won. Luckily, Jimmy outsmarted him with the "Play Dead" command which Goddard obeyed and spontaneously reassembled which Eustace's robot couldn't do and Goddard wins. In the end, Eustace's dad took Jimmy's father's advice to heart and grounded him for his behavior towards Team Neutron.
In King of Mars, he and his butler are first seen attacking Jimmy and his friends via a bug-shaped Tripod ship while attempting to remove him of his property. Jimmy manages to defeat Eustace and his butler who fall into unconsciousness after a brief battle. Eustace then plots to defeat Jimmy while on Mars and discover a special power source hidden within Mars itself so he can dominate Retroville. He is then seen in space via his tripod ship again giving a speech of his evil plan to become the first King of Mars. Eustace then kidnaps Cindy in an attempt to get Jimmy's map, which Cindy does (since she was frustrated by Jimmy always ignoring her). He then chases Jimmy to the power source only to find himself, Jimmy, Blix and Jimmy's friends captured by rogue Martians. Eustace then forms an uneasy alliance with Jimmy to save the Earth and they successfully return to Earth with the Martian's power source, not because he has a moral compass or any redeeming traits, but only for the sake of his stuff.
Eustace then teams up with several of Jimmy's enemies to deliver the final blow to him. He doesn't have much lines or screen time, but he does team up with Professor Calamitous to have Jimmy's friends dance uncontrollably for fifteen minutes.
- Since the Jimmy Timmy episodes are non-canon, he is still in prehistory with the other villains. It is possible he was eaten by one of the dinosaurs.
- Eustace was a more dangerous and serious villain in is the first appearance (as he used Jimmy's friends to hurt him and wanted Jimmy to watch Goddard get killed), but in his next appearance, he is more of a comedic villain for some reason. In season four, he would've become serious and dangerous again (since the producers were planning to keep the villain humor to a minimum).
- He is similar to Snowball from Pinky and the Brain. Ironically, Rob Paulsen is known for voicing Pinky.
- He does not like the Candy Bar, due to it only having three stars.
- He might exist to teach kids that money does not buy everything.
- His butler, Blix is often used as an "abuse dummy" for his rage or to add to him being a comedic villain.
- Eustace makes a cameo appearance in the episode Attack of the Twonkies, as he can be seen in the background watching a movie.
Main Characters: Jimmy Neutron | Carl Wheezer | Sheen Estevez | Nick Dean | Cindy Vortex | Libby Folfax | Brittany Tenelli | Betty Quinlan | Goddard