Nabbit

Nabbit is a recurring character that first appeared as an enemy in New Super Mario Bros. U and a playable character in New Super Luigi U. The name "Nabbit" is a play on the words "nab" and "rabbit". Nabbit is a thief who steals items from Toad Houses and runs away with them in his bag. He appears to be a purple rabbit with round eyes, long ears, and black limbs. He also wears a white handkerchief with a drawing of a large mouth with sharpened teeth, similar to Bowser Jr.'s mask, as well as orange shoes and white gloves.

New Super Mario Bros. U
In New Super Mario Bros. U, Nabbit appears throughout several levels. When encountered by Mario and friends, they must chase him throughout the course within 100 seconds. The heroes can also toss Koopa Shells at Nabbit, slide into him, or throw iceballs or fireballs to stun him for a couple of seconds. When Nabbit is eventually caught, Toad will take the P-Acorn out of the bag and give it to the player as a reward. If players fail to catch him three times, Nabbit will flee and disappear until conditions are met.

Nabbit appears in every world, except Peach's Castle and Superstar Road, and catching him in each of these worlds will congratulate the player. Once he is caught in the necessary worlds, he will still appear in the same levels as before after playing three levels.

The player can first find Nabbit in seven levels:
 * Acorn Plains-1: Acorn Plains Way
 * Layer-Cake Desert-6: Blooming Lakitus
 * Sparkling Waters-4: Urchin Shoals
 * Frosted Glaicer-3: Prickly Goombas!
 * Soda Jungle-1: Jungle of the Giants
 * Rock-Candy Mines-5: Walking Piranha Plants!
 * Meringue Clouds-2: Seesaw Shrooms

He also appears if the player takes too long to open the chest after defeating the enemies in an enemy course, in which case he will steal the item from the chest. To do this, it takes 30 seconds to 45 seconds.

New Super Luigi U
Nabbit reappears in New Super Luigi U, this time as a new playable character (replacing Mario from the original game). Unlike other playable characters, Nabbit cannot use power-ups (except for Super Mushrooms) or ride Yoshis, but he is immune to all enemy attacks, though he can still get knocked back by tougher enemies, such as Grrrols. Also, despite his immunity to enemy attacks, Nabbit can still lose lives by falling into lava, poison water, an abyss, simply getting crushed by certain obstacles, getting eaten by a Cheep Chomp, or running out of time.

The power-ups he collects are released as 1-Up Mushrooms at the end of the level. In single player mode, Luigi must chase him like in the original, in the same levels as in New Super Mario Bros. U. Nabbit can also be playable anytime in single player mode by holding on the Gamepad or the Pro Controller or holding the  on the Wii Remote while entering any level, except the Flying Squirrel Ovation level in Superstar Road world where Mii can be played as instead of Nabbit.

Once again, Nabbit still comes and steals the item from a chest if the player waits too long to collect a chest despite being on Luigi's side. If the player is playing as Nabbit, the screen fades after taking too long.

Mario Golf: World Tour
Nabbit appears for the first time in the Mario Golf series, as well as his first spin-off and handheld appearance, in Mario Golf: World Tour as a DLC-exclusive bonus character. He is obtained by purchasing the Flower Pack, either individually or via the Season Pass. His normal driving distance is 213 yards, while his star driving distance is 274 yards. His shot trajectory has a huge draw that travels at the lowest height out of all characters.

Super Smash Bros. for Wii U
Nabbit makes an appearance in Super Smash Bros. for Wii U in the Mushroom Kingdom U stage. After Kamek changes the stage's layout, he may appear and attempts to catch fighters in his bag. If he does so, he blasts off and takes the fighter with him, KO-ing them. However, the players can also attack Nabbit, which can release fighters in his bag and KO him.

Mario Party 10
Nabbit made his Mario Party debut in Mario Party 10 as a non-playable character. He appears if Team Mario lands on a specific space to take a Dice Block away from Bowser.

Mario & Luigi: Paper Jam
Nabbit makes an appearance in Mario & Luigi: Paper Jam. His role in the game is to provide new Bros. Attacks throughout the game if Mario and Luigi successfully capture him, effectively replacing Attack Pieces from the previous two games. At the start of the game, the trio will see Nabbit running off from Toads with several items in his sack, while dropping a Red Shell and a Fire Flower before escaping. Most of the Bros. Attacks come from catching him, except Mario's final Bros. Attack, Toad Trail, where players need to collect all the Paper Toads.

For the last Bros. Attack for Luigi, players need to fight him twice. The first time, he escapes. Between the first catch and second catch, he runs into a fight and the Trio joins. He can heal all three bros., jump on an enemy, and even has his own Bros. Attack with a Buzzy Beetle Shell that works the same as 3D Red Shell. However, it acts erratically and damages the bro who is using it if he misses it. Only Mario and Luigi can team up with Nabbit in this attack. On a side note, Nabbit has no dialogue in this game.

Mario & Sonic at the Rio 2016 Olympic Games
Nabbit is set to appear as a new playable character in Mario & Sonic at the Rio 2016 Olympic Games.

Trivia

 * The character Ravio from The Legend of Zelda: A Link Between Worlds has a similar appearance to Nabbit, as pointed out by several fans in the comments of a Miiverse post with an in-development screenshot showing the character. However, Satoru Iwata, during the October 1, 2013 Nintendo Direct, officially dismissed the similarities as an unintentional coincidence. Although, Iwata added that because the developers work so closely together it is not surprising that similar designs could manifest in different, unrelated games.
 * Nabbit seems to inhabit the purple Records Toad House, as it is filled with item bags like the one he carries and has his silhouette visible on the ceiling.