Bob first appeared in the season 1 episode "The Telltale Head", where he plots to murder Krusty. Since then, he has appeared in several episodes throughout the series, often trying to frame Krusty or harm the Simpson family. He has also been shown to have a soft side, such as in the episode "Sideshow Bob's Last Gleaming", where he forms a bond with Bart Simpson.
Sideshow Bob is a complex character who is both threatening and sympathetic. He is a criminal mastermind who is capable of great evil, but he is also a broken man who is haunted by his past. He is a reminder that even the most evil of people can have redeeming qualities.
Sideshow Bob is one of the most popular characters in The Simpsons. He is a great villain and he always provides a lot of laughs. He is also a symbol of the dark side of show business and a reminder that fame and fortune can come at a price.