Eustace Bagge is Muriel's sarcastic, sardonic, funny, , pessimistic, and skinny husband. An old farmer obsessed with money and his truck, Eustace is also the current owner of the farmhouse which was previously owned by his now deceased brother, Horst. He has a very sardonic personality; he frequently mistreats Courage and calls him a "stupid dog". Eustace is known for his trademark glasses, which are identical in appearance to Muriel's, and his brown hat which shields his bald head. Eustace often refers to Courage simply as "Dog" and rarely (in only 2 episodes) addresses him by his name. He regularly demands Muriel as well; in one episode, Muriel develops amnesia and Eustace convinces her that she is a "slave woman".Still, he does love his wife, as evidenced by his concern for her well-being in a few episodes.
In many episodes, whenever Muriel is in danger, Eustace will often be preoccupied with something else and not even notice or he will just choose to not even acknowledge the fact that his wife is in danger, which often leads Courage to save Muriel on his own. Eustace is also commonly the subject of a rather unpleasant ending, whether it being a backfire of his get-rich-quick scheme or the villain of the episode going after him or, better yet, he gets his just-desserts at the end, often in quite brutal ways.
Eustace takes great pleasure in terrorizing Courage despite the fact that he frequently saves him from the monsters that terrorize him and Muriel, which primarily stems from jealousy of the attention he receives from Muriel, as well as similar abuse he received from his mother and his brother, which led to him feeling like an outcast; However, it is unknown on how his father treated him. The most common of his scare tactics against Courage is Eustace pulling out a large green painted mask with a crazy looking in its eyes and shouting, "Oooga-booga-booga!" for laughs. Although Eustace primarily uses the mask, he has substituted it with other things that terrorizes Courage. His sarcasm towards Courage often results in Muriel bashing him over the head with a rolling pin or whatever else may be handy at the time, usually causing him to respond with "Ow! What did I do?". During these attempts to harm Courage. On occasion, though, Eustace would team up with Courage, mostly when money is involved, though once he did it to exorcise a demon from Muriel, and once to rid Muriel of the "weremole" from another episode. Eustace hides a mallet under his bed for protection.
Lionel G. Wilson originally voiced the character, but left midway through the third season due to illness (and eventually died a year after the show ended) and was replaced by Arthur Anderson. However, some vocals and sounds of grunting, screaming and catchphrases from Lionel have been used while Arthur was recording. In the 2014 short titled The Fog of Courage, Wallace Shawn replaced Anderson as the voice of Eustace.
- Eustace is only seen without his glasses in "The Chicken from Outer Space" "The Curse of Shirley" and "Le Quack Balloon". But most of the time, he never takes them off even when sleeping or taking a bath, like Muriel.
- Eustace has an old farm truck based on a Chevrolet 1½-Ton.
- Eustace has his own theme music.
- Surprisingly, Eustace actually called Courage by his name instead of the usual "stupid dog." in The Hunchback of Nowhere, Ball of Revenge, and the Cartoon Network 20th Anniversary Party bumper.
- There is a running gag where he either gets hurt, possessed, or killed at the end of the episode with the exeption of Freaky Fred or The House of Discontent.
- His personality was based on John R. Dilworth's early incorrigible attitude.
- It's revealed in Bad Hair Day that the reason he calls Courage "stupid dog" is because of his mother calling him "stupid boy ".
- Eustace Bagge will have a job of the Growth Industries as a new CEO in the future.