Shimmering Land

[Killer Joe]

Mountain Lake
Land
Tap: Add one colorless mana to your mana pool.
Tap: Choose Blue or Red. Add the chosen colored mana to your mana pool. Mountain Lake will only produce the chosen color or colorless as long as it remains in play.

UW=Meadow Lake
UB=Swamp Lake
BR=Mountain Swamp
RG=Mountain Treeland
GW=Treeland Meadows

WB=Swampy Meadows
UR=Mountain Lake
BG=Treeland Swamp
RW=Mountain Meadows
GU=Treeland Lake

I'm not much for creative names .

 

[FoundationOfRancor]

Rewording

Mountain Lake
Land
When ~this~ comes into play, choose eithre Red or Blue.
T: Add 1 to your mana pool.
T: Add one mana of the chosen color to your mana pool.

 

[Killer Joe]

I just thought it would be cool to not have to choose the color until you really needed it, and just use it as colorless until then.

 

[FoundationOfRancor]

Ohh...

In that case, I think you came pretty close to the right wording, you should cut the "or colorless" part on the second ability.

There ok, overpowered. CIP would be fine.

 

[sageridder]

Mountain Lake
Land
Comes into play tapped
Tap: Add one mana to your mana pool.
Tap: Choose Blue or Red.mountain lake becomes the chosen color,and may be only be tapped to produce that color mana.

 

[Sammy Dead-O]

WU = Illuminated Study
UB = Murky Beach
BR = Cremation Grounds
RG = Petrified Forest
GW = Oak Cathedral; Oak Orchard; Fruit Orchard

WB = Churchyard Cemetery; Demonic Councilhouse
BG = Coffin Stockyard
GU = Kelp Patch; Mossy Sandbar
UR = Geyser; Alpine Library; Alpine Waterfall
RW = Terraced Farmland