Understanding what these five phases are and how they work is an essential part of understanding gameplay
After you move your venture marker into the last room of a dungeon and that room's ability resolves (or otherwise leaves the stack), the dungeon leaves the game and you have now completed it
This spell destroys all nonwhite creatures, so it can affect your Sire of Seven Deaths and Crystalline Giant, and won't hurt your opponents' white creatures, including those that are multicolored
Although it has its downside, its one of the cheaper ways to end the turn
Understandably, we got a lot of questions
Outside of these environments, Urza can still be quite good, as he generates 2 bodies for 4 mana, provides a mana sink with a powerful payoff when needed, and can even turn things like Equipment and Sapphire Medallions into tools to race ahead of your opponents while still employing their inherent value