AAAHH!!! Real Monsters
At the title screen, hold R + up, and press A 7 times, then hold L + up, and press Y 8 times, then hold L + R + up, and press B 9 times, and finally hold up, and press X. Note that you'll only have about five seconds to enter the code.
Contributed By: ZeldaGuy and LuigiSan.
Grumble is the monster who appears while a level loads.
Make Grumble Angry:
To make Grumble angry, hold R and Down on the D-Pad.
Make Grumble Blink
To make Grumble blink, simply press L or R.
Contributed By: dot com.
When the Nickelodeon logo appears on the screen, press any direction on the control pad to start the theme music. Now press A, B, X, or Y to make sounds.
Contributed By: Dogg.