Daxter

There is a box behind the warp gate to Emerald Isle in the City Port area that you can jump onto. Jump up on it, then go behind it and turn back the way you came. You will see the back of the box has a picture on it. Smash the picture, then go inside the box to find the Sly Cooper Mask.

Unlock the last dream with 500 Precursor Orbs (The Lord of the Rings II level with Daxter as Gandalf). The fire beast is The Oracle from Jak 2 and Jak 3.

These codes are normally unlocked by getting a "Gold" rank in a mini-game:

Clue A: 32X83R
Clue B: 68T7E5
Clue C: 5A3D36
Clue D: 7A8J25