Mystery Booster/Test cards

The Convention Edition packs of the Mystery Booster contain a pretend "playtest card". They are referred to as test cards on the cards themselves.

Description
The test cards feature black and white card faces that look like they have been stickered on cards with a regular card frame of the appropriate color. The card names are pretended funny placeholders, and the cards lack Collector numbers and artist credits (the "temporary" illustrations are created by various R&D members ). Test cards are not meant for Constructed play, but may be used in Chaos Draft. There is a total of 121 test cards (one print sheet ).

Test cards are not considered to be “real” cards, not even considered silver-bordered. They were more meant as entertainment than as game pieces. The test cards haven't undergone rules scrutiny, and Play Design hasn't tested them rigorously for balance.

Rulings

 * Playtest cards aren't legal for play in any tournament format other than Mystery Booster Limited formats.
 * 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.
 * Playtest cards often use "CARDNAME" in place of the card's own name. This follows the same rules as an object referring to itself by name.
 * For many playtest cards, you'll need to make a generous assumption that basic game rules will be updated to allow them to work.

Themes and mechanics
The test cards explore various themes and mechanics. This is similar to how Future Sight tested out new mechanics that later appeared in regular sets.

Examples of new or revisited themes are turn matters, games matter, hand size matters, quadrupling, card tokens (land tokens, enchantment tokens, sorcery tokens), the plot booster and the Whammy deck.

New mechanics are: Aggressive, Bank, Challenge, Enchantment land, Firstest strike, Four-faced, Interplanar, Keyword counters, Kinfall, Landship, Legacy, manabond counters, Megalegendary, Motivate, Ransom, Reflect, Requirement, Reverse miracle, Scrycast, Spark, Spellmorph, Tasty, Token cards, Underdog and Upgrade.

Returning
Returning mechanics (some with new twists) are Annihilator, Arcane, Buyback, cards from outside of the game, Flagbearer, Haunt, Land creatures, Planeswalk, Poison, Storm, Banding and Vanguard.

Named
Mill and Fizzle are used as terms on cards for the first time.

Card types
Cloud is a new Basic land type. Abian and Duck are new planeswalker types. Locus is used as a creature type, instead of as a land type. Alien, Aven, Beholder, Half and Phyrexian are new creature types. Lobster is used for the first time as a creature type on a printed card. Dog, Gorilla and Mammoth are reintroduced. Key is a new artifact type. Elemental is a new type (not to be confused with the Elemental creature subtype).

Two cards features an Instant Creature, one of which also can turn other creatures into Instant Creatures as well.