Note: The Brown and Gray ID numbers are missing because this part number does not belong to this part. 42042 is called “BIONICLE GIMMIC” in the parts database.
The 42042 ID is a catch-all for the various masks used in the 2002-03 Bionicle run, much like the Kraata IDs are a catch-all for the different stages one can find. Each Krana mask should have all 19 ID numbers, including the unused Pearl Black ID. That part was originally supposed to appear in set 8573.