Eustace Bagge is an elderly farmer, and he is Muriel's husband and Courage's other owner. He has a very negative personality; he is idiotic, greedy, grumpy and selfish; he is obsessed with his truck, and frequently abuses Courage and calls him a "stupid dog". Sometimes, a villain would call Courage a "stupid dog," prompting Eustace to say That's what I tell him all the time. You stupid dog, you stupid dog. Eustace often simply refers to Courage as "Dog", and rarely (in only 2 episodes) addresses him by name. He regularly mistreats or neglects Muriel as well; in one episode, Muriel develops amnesia and Eustace convinces her that she is his slave. 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. He takes great pleasure in scaring and physically harming Courage, which primarily stems from jealousy of the fact that Muriel pays more attention to Courage than to him; however, he has also been known to scare Courage just for laughs or simply to get Courage to stop bothering him. The most common of these scare tactics against Courage is Eustace pulling out a large painted mask with a crazed look in its eyes and shouting, "Oooga-booga-booga!". His cruelty 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 "What did I do?".
A running gag throughout the series is when Courage manages to defeat a villain in each episode, Eustace often suffers some horrible fate, such as being kidnapped, mummified, possessed, eaten, horribly disfigured, ejected into space, or even killed, though he is alive and seemingly unhurt in the next episode. Eustace also replaces the word "my" with "me". Often, Eustace's extreme greed causes trouble for Courage, leading either to Eustace becoming a villain of an episode or Eustace agreeing to aid a villain with their schemes in exchange for cash. Despite his gruff and selfish nature, he occasionally shows compassion and has worked alongside Courage to save Muriel more than once. Though few and far between, he can even have memorable moments of kindness. A well known example of this is in "The Curse of Shirley", where Eustace is cursed by Shirley, and a cloud starts to rain on and follow Eustace. Later on, he loses his glasses in the process, but, due to his blindness and the help of a magical mirror, he mistakes Courage for his young and suffering self (apparently the only person he would actually want to help), and graciously gives Courage his hat. This releases the spell on him and pleases Muriel. He had a father named Ickett and a manly older brother named Horst (with whom he never got along), who are both deceased. He also has a mother, who is simply called Ma, but she dislikes Eustace and is more fond of Courage, further adding to his deep-seated contempt for the latter. Despite Eustace's selfish nature, he still loves Muriel, and does tasks around the house when asked to do so, even if he does complain and say "ba ba ba" about it all the while; however, he will just as often dump these chores on Courage. Eustace also keeps a giant mallet under his bed, typically to threaten trespassers or to kill mice. A great example of this would be when Eustace states that there are mice in his house and says "Got to get me mallet."
Eustace wears a light yellow zip up collared shirt, dark green overalls, black shoes and a brown hat. He also fair skin and wears glasses, his eye color is confirmed to be blue.