At Spaceworld 2000, Shigeru Miyamoto showed off a prototype for the GameCube controller. The most glaring difference between this controller and the final design are the color and shape of three buttons:
• The A button being blue, like the Z button rather than green, but keeping it's circular shape
• The B button being green, like the final A button rather than red, and bean shaped like the X and Y buttons rather than circular
• The start button being red like the final B button as well as being bulbous and protruding as compared to the final start button being flat, grey, and made of rubber

An accompanying tech demo used assets from Luigi's Mansion including one of the basic ghosts which reacted differently depending on what button was used:
• Using the A, B, X, and Y buttons made it spit out the corresponding letter
• Stretching for the L button and squishing for the R button
• Emitting a slower version of Boo's laugh for the Z button
• Emitting a normal ghost noise for the control stick
• Changing orientation for the C-stick
• Emitting sounds similar to that of Pikmin for any of the D-pad directions

The inclusion of the Pikmin noises makes sense as Luigi's Mansion contained a trailer for Pikmin upon release.