Blood Feud is the twenty-second and final episode of Season 2.
Homer discovers that Bart has a rare blood type that can save Mr. Burns' life, Homer convinces Bart to give blood (in the hopes that Burns will give the Simpsons a cash reward), but when all Burns gives Bart is a "Thank You" card, Homer writes a nasty letter to Burns which ends up getting sent to him by Bart.
Mr. Burns becomes seriously ill and is diagnosed with hypohemia, an infection that leaves a person without enough blood to sustain life. Desperate to save his boss, Smithers issues a plea to the plant's employees for a double-O-negative blood donor. Thinking Burns will reward him richly, Homer volunteers, but he does not have the right blood type. Bart happens to be a match, and Homer has him donate blood to his boss. Bart is reluctant to do so, despite Marge's coaxing that one human being should help another. Bart is finally won over after Homer tells him of a concept that "save a rich man's life, he will shower you with money". After the transfusion, Burns is more alive than ever. He even plans to pen his autobiography.
Homer deems Burns' meager thank-you card to be an inadequate response to the gift of life. He immediately writes Burns a venomous letter, but Marge prevents him from mailing it. The next morning, Homer is grateful that Marge's cooler head prevailed and goes to tear up the letter. Unable to the find the hate-filled note, he discovers that Bart has already mailed it. Homer tries unsuccessfully to retrieve the letter, but Burns sees it. Furious, Burns vows to make Homer's life miserable.
First, Burns signs Homer's pink slip, then he orders Smithers to have Homer beaten to a pulp, but Smithers refuses, explaining that he is unable to harm the man who saved his boss' life. Coming to his senses, Burns realizes the good deed the Simpsons have done, and buys them an extravagant present, a rare Olmec Indian head statue. Bart thinks it is cool, but Homer does not think it is a fitting reward. The family is unable to choose on the moral of the story or even if it has one. However, they do agree that it has been a memorable few days.
Behind the Laughter
The episode was written by George Meyer and directed by David Silverman. Executive producer Sam Simon and writers Al Jean and Mike Reiss came up with the idea for the episode. A co-worker had recently needed a blood transfusion and the writers thought it would be funny if Mr. Burns had one. Although Meyer was credited with writing the episode, Jean and Reiss re-wrote and polished the script.
The episode includes the debut of the Olmec head Xtapolapocetl, which would become a common background prop in the Simpson home.