I think you're trying to make a card that lets you tap an opponent land and put mana. However...
Does the opponent land have to be untapped?
If yes, then this card is... kinda odd, and probably doesn't work the way you'd think it does. An opponent can just tap his lands when he isn't using them. What is does is it's a repeatable rishadan port that costs life and has a severe drawback in letting your opponent have 5 color mana. I suppose if you have the life to spare, you can keep your opponent's mana pinned down.
If no, then this card is broken as hell, because it's now a 0 cost repeatable uncounterable 5 color channel.
If you put a tap cost to prevent channel shenanigans, it would still make this card much, much worse than city of brass unless you combo it off boil or something.
Type: Legendary Land
Effect: All of your opponent's basic lands become all basic land types.
Pay 1 Life: Tap 1 of your opponent's basic lands in place of 1 of your own lands when playing your own spells.
Does the opponent land have to be untapped?
If yes, then this card is... kinda odd, and probably doesn't work the way you'd think it does. An opponent can just tap his lands when he isn't using them. What is does is it's a repeatable rishadan port that costs life and has a severe drawback in letting your opponent have 5 color mana. I suppose if you have the life to spare, you can keep your opponent's mana pinned down.
If no, then this card is broken as hell, because it's now a 0 cost repeatable uncounterable 5 color channel.
If you put a tap cost to prevent channel shenanigans, it would still make this card much, much worse than city of brass unless you combo it off boil or something.
"Sometimes, the situation is outracing a threat, sometimes it's ignoring it, and sometimes it involves sideboarding in 4x Hope//Pray." --Doug Linn