Keycard

Found on the final level in both golden containers and dropped off of monsters. They can open up doors to rooms in the center of the ship before the boss. There are 4 rooms in total, meaning you will need 4 keycards if you intend on opening all the doors (this can be done with only two keycards with the proper items; see the "Secrets" section of the final level). Collecting four keycards in one game will also unlock the Wicked Ring (you do not need to be holding them all at once, as in if you had 3, used 2 and got 1 more it would work). The player who picked up the keycard is the only one who can unlock the door; make sure to pay attention to who picks them up, as sometimes they won't notice.

Most of the time every cargo room contains one golden container.

Keycard