Naked Singularity

Artifact    (CMC:5)

Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) If tapped for mana, Plains produce , Islands produce , Swamps produce , Mountains produce , and Forests produce instead of any other type.

216 ME4 • ENMark Tedin

™ & © 1993—2011 Wizards of the Coast

Legal in: Ice Age Block,Legacy,Vintage,Commander

Oracle Text (click to copy):

10/4/2004
The ability generates a replacement effect.
10/4/2004
If a player uses a text-changing effect to make a land type be listed as producing two different colors, the player tapping the land for mana can choose to produce mana of either color. But if it produces more than one mana, all mana is of the same color.
4/15/2013
If a land has more than one basic land type, the player tapping the land for mana can choose to produce mana of either color. But if it produces more than one mana, all mana is of the same color.