Balanced?

Perhaps, but extremely gross. This would be behated by EDH players for years to come.

In fact, I hate this card just looking at it. It's powerful enough without all of the tacked-on keywords. I'm just glad it can't be played in Animar or Roon decks.

Well. Realm Razer exists. As does Desolation Giant.

And I think there's something to be said for making nonbasic hosing a little more playable as a way to encourage people to play more basic lands.

This card is sensibly costed enough to make it almost unplayable in tournaments - it won't be big enough in most duels unless the metagame is particularly nonbasic-happy. It's clearly venues like EDH where it'll shine (or attract a lot of growls).

Which is a better-designed card, this or Wipe Blank?

@Alex: That depends on the format. It would have been a powerhouse against the good stuff decks from the original Ravnica block, what with their dependency on non-basics, and their willingness to cast 8 drops. But it is an irregular format where this card becomes king, true.

@Samuel: I guess that depends, too. Wipe Blank seems more likely to see print. If you're trying to win a design contest, though, I don't think it will turn as many heads as World Swallower. If I may make a suggestion for the Swallower, though? How about changing "destroy all nonbasic lands" to "destroy any number of target nonbasic lands"? That way, you can sacrifice your own nonbasics, but you don't need to throw yourself under the bus. Mythics tend to be all upside anyway.

Hmm... and I guess I got to agree with Alex. This could shave at least a and still be fine. It's tough to figure out how far you could go, though. Very swingy.

All of my hate comes from EDH. This would be fine in most other formats.

Would it work if it said "each opponent sacrifices half the lands they control rounded up/down" or something like that? That would have a similar effect, but not have the random element of completely hosing some decks and doing nothing against others.

I also would like to see more drawbacks on non-basic lands, but I'm not sure "a small chance of a complete blowout" will have the desired effect.

I don't know, Jack... it does water the message down. And it also encourages the card to cost less. In my mind, it's better to pay a lot for a crazy, swingy event than to make a Mythic rare pull half-measures so that it isn't as offensive.

Or maybe, "all but two"? Or, just "all lands"? I'm not sure. I feel like, if someone is putting this in their deck as an answer against decks that play ridiculously many non-basics, that's good. But it's more likely it'll come up rarely enough no-one will alter their mana base for it, so it will just randomly be either "destroy all lands" or Goblin Striker, and either way one player will be disappointed. But maybe I'm too pessimistic.