Sideshow Bob

Sideshow Bob is a unique, non-controllable character in The Simpsons: Tapped Out. There is a 10% chance of him randomly appearing in the player's Springfield.

Simpsons Wiki Description
Robert "Bob" Underdunk Terwilliger, Jr., better known by his stage name, Sideshow Bob, which he got when he was Krusty the Clown's sidekick. Bob is a self-proclaimed genius, member of the Republican Party, champion of high culture, former children's entertainer turned criminal mastermind and Bart Simpson's arch-nemesis. He loves Gilbert and Sullivan Operettas and is known for his huge feet, which have gotten him into trouble on more than one occasion.


 * Read the full article here at Simpsons Wiki.

About
Sideshow Bob is a unique character. He cannot be controlled, nor obtained by the player. In the game, there is a 10% chance of Bob appearing randomly, the game claiming that he had escaped from imprisonment. Upon his appearance, Bob will run among the player's Springfield. The player must then tap Bob to apprehend him before he seeks shelter in a building.

Upon apprehending Bob, the player will be awarded a small portion of experience, along with a boost to the Righteousness category of their Conform-O-Meter. This is the only way to gain Righteousness in-game without having friends to vandalize your Springfield.

Sideshow Bob will first appear in the player's Springfield at Level 6 along with a task, and will then randomly appear from then on.

Trivia

 * Sideshow Bob's character icon can only be seen when the player is assigned the task to apprehend him on his first appearance in the game.
 * As of the Whacking Day Update, Sideshow Bob appears more often, the chances increased from 1% to 10%.