This door glows strongly of magic, and is
in fact resistant to all forms of wizardly or thiefly opening. The weave here is
also strongly resistant to any spells that would allow this door to be bypassed in
any way.There are two round holes in the door, and attached to the wall is a box with two holes over one hole. The holes are 3" diameter.
If the party has access to the proper keys (located elsewhere), they can use them to open this door. There are 4 balls, each is 3" diameter. One is Red, Blue, Yellow, and White.
The white one, if placed in the door, will discharge 10d6 electrical damage that fills the room. Likewise, the red one will discharge 10d6 fire damage, the blue one will discharge 10d6 ice damage, and the yellow one will blind the party for an hour.
The trick is to use the box to mix the colors, by inserting two balls at once, one rolls out. Then the party must use the mixed color balls to open the door. The DM may determine what color combinations work.