Things You'll Need
Instructions
Insert your Action Replay cartridge into your Nintendo DS and turn on the handheld using the "Power" button.
Remove the Action Replay cartridge and insert the Pokemon Pearl cartridge when prompted.
Choose the option to put in your own codes and type the following commands:
94000130 fcff0000
b21c4d28 00000000
b0000004 00000000
10001170 000001ee
d2000000 00000000
Start the game as normal, and go to the mining museum. Talk to the man behind the counter by pressing the "A" button and he will give you a glitch egg.
Set Lugia as the first Pokemon on your team, then put the glitch egg as another party member. Battle the Elite Four, and the glitch egg will change into Dark Lugia.