Comet is a golden retriever which was introduced on the show in season three. He was born to a dog named Minnie. In a few episodes, Comet was played by a dog named Buddy. Buddy was born in 1988, but died of cancer in his sleep on February 10, 1998.
Comet's "mother", Minnie, (who was actually male in the storyline) ran away from her home in Ohio, and somehow ended up in the Tanners' backyard in San Francisco, California while she was pregnant. Minnie gave birth to a litter of puppies (which included Comet) on Jesse's bed. Minnie's owner then arrived at the Tanner residence shortly after Minnie gave birth. Once he arrived, he was so grateful that the Tanners had taken care of Minnie and her puppies, and he allowed them to keep one of the puppies. Michelle chose which puppy they would keep, and whom they named "Comet". Although based on Minnie's dog tag stating her home address is Ohio and the Tanners' assume she ran all the way to San Francisco, at the end of the episode Stephanie asks her owner if she "can come over sometime to visit the puppies". This implies that it's likely Minnie and her owner recently moved to San Francisco from Ohio, which would make more sense for her running away than doing so across the country.
In the episode "Comet's Excellent Adventure" (season eight's premiere episode), Michelle was constantly reminding Jesse, while he was busy talking on the phone, that it was his turn to walk Comet. In the heat of the moment, Jesse told Michelle to walk Comet herself. Michelle was only seven years old at the time, and not very strong, so Comet ran away from her. Since Michelle was not allowed to cross the street, she only followed Comet to the end of the sidewalk. Comet spent the day exploring the city of San Francisco with a female collie. Danny Tanner and Becky happened to be broadcasting their talk-show live at the time he was informed about Comet's disappearance, and he abruptly announced the news to his viewers, and let Michelle say some words to Comet as well. When Comet saw Michelle's message on a television in the window of a local store, he immediately ran back home. He might be dead so he wont be in the spin off.
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