Young Cricket

Young Cricket and Master Mantis are two characters first appearing in WarioWare: Smooth Moves. They are said to be roaming the world in search of new poses, suggesting that they already know about the Form Baton. When they are first introduced, they appear to be rather serious characters, shown training through tough conditions, but it is then revealed that they "fit in" with the rest of Wario's "friends".

WarioWare: Smooth Moves
Young Cricket and Master Mantis make their debut in WarioWare: Smooth Moves. Their story starts with the two characters being very hungry. They find a place to buy dumplings. Cricket starts running on people's heads to the front of the line. Then the game starts. Every time a microgame is lost, one dumpling is taken by someone. When getting an extra life, a new one is laid on the table. Eventually, Cricket reaches the front of the line, only to be looked down upon by the people he stepped on. He runs on their heads again back to Master Mantis and tells him that they should get in line.

WarioWare: D.I.Y.
In WarioWare: D.I.Y., they run the Assembly Dojo. They also appear as comic stamps.

Game & Wario
Young Cricket and Master Mantis also appear in Game & Wario, where they host the Kung Fu minigame.

They are also seen as bowling pins in the Bowling minigame (like most characters in the game).

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, Young Cricket has a Sticker. It raises a player's attack by three.

Super Smash Bros. for Wii U
In Super Smash Bros. for Wii U, Young Cricket can be seen on the sketchpad in one of randomly generated layouts for the Gamer stage.

Rhythm Heaven Megamix
The pair makes an appearance in the Wario... Where? version of Rhythm Heaven Megamix. The set's version of Munchy Monk features Master Mantis in place of the monk and a cloud-riding Young Cricket as the person handing the dumplings.

Young Cricket
-Master Mantis's apprentice -Student of We-Yu-Ken -Recently mastered We-Ken -Loves dumplings

Master Mantis
-Master of countless martial arts -Popular with the ladies -Has his own fan club -Loves dumplings (a bit too much)

Trivia

 * Young Cricket, or a very similar character, appears in Rhythm Heaven Fever in a 2-Player Endless minigame called Kung-Fu Ball. Here, he is seen punching/kicking a ball back and forth between a girl character, dressed similarly as him. The Rhythm Heaven series is also made by the WarioWare team.