If you destroy an emblem with Naturalize 2, put that emblem into its owner’s graveyard. Then it’ll immediately cease to exist except in the very rare instance that it’s an emblem card like Essence of Ajani.

As of the release of Mystery Booster 2, the following gameplay trackers can be destroyed with Naturalize 2: The monarch, city’s blessing, dungeons, day, night, and the initiative.

You can destroy the monarch designation with Naturalize 2. This abolishes the monarchy from the game. There will no longer be a monarch until another spell or ability causes a player to become the monarch once more.

You can destroy a player’s city’s blessing designation with Naturalize 2. That player no longer has the city’s blessing. They can regain the city’s blessing if they control a permanent with ascend or resolve an instant/sorcery spell with ascend while controlling ten or more permanents.

You can destroy a dungeon with Naturalize 2. Doing so removes that dungeon from the game and removes its owner’s venture marker from the game. Nothing prevents its owner from venturing into that dungeon again if another spell or ability instructs them to, though they would have to start from the topmost room again. Note that each dungeon has a single owner; even if two players are venturing through two dungeons with the same name, each of them owns a separate dungeon card.

You can destroy the day or night designation with Naturalize 2. Doing so removes those designations from the game. It will be neither day nor night until a player controls a permanent with daybound or nightbound, or a spell or ability says “it becomes day” or “it becomes night.”

You can destroy the initiative designation with Naturalize 2. Doing so removes the initiative from the game, though this doesn’t affect any existing dungeons in the game. No player will have the initiative until another spell or ability causes a player to take the initiative once more.

Playtest cards aren’t legal for play in any tournament format other than Mystery Booster Limited formats. On the other hand, we expect they will spice up a wide variety of non-tournament games (as long as everyone’s on the same page about using them!).

Playtest cards use a modified version of game symbols, such as {T} and {W}. These modified symbols should be treated as the standard symbols during play.

For many playtest cards, you’ll need to make a generous assumption that basic game rules would be updated to allow them to work. The Mystery Booster 2 Playtest Card Notes section (reproduced here in individual Gatherer rulings) provides guidance for fitting these cards into the existing rules structure.