Urborg isnt Mutavault its neither as good nor as versatile but its the closest thing to it in M15
On top of that, all damage is now dealt with wither, meaning it remains on creatures as -1/-1 counters instead of temporary damage that heals in the end step
Arcee, Sharpshooter is a 2/2 creature with first strike, and you can pay one generic mana to remove any number of +1/+1 counters from it to deal that much damage to a creature
Every deck is built around a legendary creature, or commander
(Treat it and anything attached to it as though they don't exist until your next turn.) Phased-out permanents are treated as though they don't exist
In a typical situation, if our Colossus did not have indestructible, the Recluse would kill it, sending them both to the graveyard