Trick Dice (3.5e Equipment)
From D&D Wiki
These white pair of bone-carved cubes appear to have black dots, from one to six, painted on each side. The dots are actually a permanent illusion along the surface of each die. With a thought, the roller can will the illusion to alter and land in any combination of dots. The combination must be thought of clearly before the dice are tossed. This works for a single die as well as two or more.