Mouser is a character from the Mario series. His first game was Super Mario Bros. 2, or in Japan, Doki Doki Panic. He is a mouse, with sunglasses, a big body, and red gloves and shoes. In Super Mario Bros. 2, he would throw bombs at whom ever would come near him, which was either Mario, Luigi, Peach, or Toad, the game's playable characters.

He is a minion to Wart, the evil frog who takes over Subcon. But unlike Wart, Mouser seems to have become more popular, on the account that he has appeared in many more games than Wart.

In Super Mario World 2: Yoshi's Island, Mouser doesn't make an exact appearance, but his species does. In this game, they appear as a smaller type of Mouser without glasses, these mice are also enemies. Another game is Paper Mario, where it reveals that the ruler of these mice's name is Nomadimouse, whom helps Mario. This species has also appeared in Paper Mario: The Thousand-Year Door, with one of the party members for Mario. Her name is Ms. Mowz.

The most recent appearance is in the game Mario Party Advance, where Mouser makes an appearance as a boss in the Duel Tower. Though it's not confirmed whether or not the appearances from Yoshi's Island, or the Paper Mario series characters are Mouser's species, this appearance is, on the account that it is Mouser.

Outside of the games, Mouser was a regularly-featured character on The Super Mario Bros. Super Show, where he appeared as King Koopa's second-in-command. He also appeared a few times in Valiant's Super Mario Bros. comic books, playing a similar role to that on the Super Show. The comics notably revealed that he was formerly the king of a race of identical mice who live in the Mushroom Kingdom's sewers, but was eventually corrupted by Bowser.