The Transform Costume is an item that appears in the inventory of Silent Hill 3 as an unlockable costume. After entering "PrincessHeart" into the costume typewriter, the Transform Costume will automatically appear in the inventory on an Extra New Game.
Using it activates a Sailor Moon-esqe sequence where Heather Mason transforms into Princess Heart. The costume allows Heather to run long distances without tiring, and also, if unlocked, allows the use of the Sexy Beam.
In Silent Hill: Book of Memories, it returns as an Expansion Pack weapon. The player can shoot laser beams with their eyes.
- The item is most likely an homage to the Sailor Moon series, as it is rife with transformation sequences and bejeweled accessories. It is very reminiscent of a generic transformation sequence in Japanese anime.
- Unlocking the costume in the Silent Hill HD Collection gives the Achievement "Where's Luna?"