The family at the core of The Simpsons has been around for thirty years now, and in that time we've gotten to know dozens of the other residents of Springfield as they came and went, and came back again. However, there are a few characters that only appeared on the series once. Whether that's because the voice actor didn't want to repeat a performance, or there just wasn't a story fit for them, they became one-hit wonders. If you can recall the one episode these characters were in among the hundreds that have aired, then you're in rarified Simpsons fandom territory. Meet five of those characters at TVOM.