The Mayor of Trovitopolis (in Japanese: ビッグシティの市長 Mayor of Big City) is a character of the day in the anime episode "The Mystery Menace" of Pokémon.
While Ash and his friends were heading through Trovitopolis on the way to Trovita Island, they landed in the sewers after one of Team Rocket's attempts to steal Pikachu went wrong. The Trovitopolis Officer Jenny found them down there after Ash's Bulbasaur got kidnapped by a creature. After Ash and his friends got out of the sewers, they were locked in jail. The mayor wanted to get rid of the creature in the sewers so he could get re-elected, and hired a personal SWAT team to carry out his needs by guarding every sewer entrance in the city. However, after sealing all the exits in the sewers, it turned out the mayor was more concerned about getting re-elected than what was going on down below.
As Ash and his friends were looking for Bulbasaur, Misty and her Togepi got captured, too. It later turned out a Bulbasaur that was twice its normal size was the creature wreaking havoc. It was lonely after being abandoned by the mayor when he was a child and was looking for someone to keep it company. Ash, Misty, and Tracey then showed the whole town that the monster was the Bulbasaur that the mayor previous owned, after the pipes got backed up from the concrete-sealed sewer exits and flooded Trovitopolis City Hall.
The mayor revealed the fact he abandoned the Bulbasaur because it wouldn't evolve. He unhappily decided to punish Bulbasaur for not evolving. After hearing what happened, the townspeople refused to vote for him. Misty demanded the mayor an apology, but he refused. He was put away, and the town's Nurse Joy agreed to take care of the Bulbasaur.