Computer
Wario's computer is a laptop that he uses to set up his microgames in WarioWare, Inc.: Mega Microgame$! The menu and select screens are also made to look like it is on the Game Boy Advance screen. Wario has all of the microgames stored on it and when he unlocks a new one by playing it, it appears on the screen with all of the minigames.
Wario's computer reappears in the intro sequence of Game & Wario with Wario typing on it after calling his friends, and again in the intro of Arrow where it is covered in dust as a reference to its long absence until Wario sneezes the mouse into the computer, giving him the idea to develop the Arrow game.
Wario's computer makes a brief cameo in WarioWare Gold when Wario streams his announcement of the Wario Bowl games.