Lands you control are Plains. Nonland permanents you control are white. The same is true for spells you control and nonland cards you own that aren't on the battlefield. You may spend white mana as though it were mana of any color. You may spend other mana only as though it were colorless mana.
When Celestine Cave Witch enters, create two 1/1 black Insect creature tokens. Whenever Celestine Cave Witch attacks, you may sacrifice an Insect. When you do, curse defending player. (Create a black Aura Curse enchantment token that's attached to that player. It has enchant player and "At the beginning of your upkeep, you lose 1 life.")
Creatures without flying or islandwalk can't attack. Whenever chaos ensues, until a player planeswalks, you can't lose the game and your opponents can't win the game.
Flying, lifelink Healing Tears — At the beginning of your end step, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of life you gained this turn.
Hideaway 5 At the beginning of your upkeep, you may mill three cards. Then if there are twenty or more cards in your graveyard, you may play the exiled card without paying its mana cost.
{W}, {T}: Put a +1/+1 counter on target Soldier creature. Each creature you control with a +1/+1 counter on it can block an additional creature each combat.
"A well-trained force brings peace... which brings more time for training!"
Trample This creature enters with a number of +1/+1 counters on it equal to the number of land cards in all graveyards. Whenever a land card is put into a graveyard from anywhere, you may pay {G}{G}. If you do, return this card from your graveyard to your hand.
When this creature enters, roll five six-sided dice and store those results on it. At the beginning of combat on your turn, you may reroll any number of this creature's stored results. This creature gets +X/+X, where X is the greatest number of stored results on it of the same value.
When you unlock this door, search your library for a Room card that doesn't have the same name as a Room you control, reveal it, put it into your hand, then shuffle.
This creature can't be blocked. At the beginning of combat on your turn, you may have this creature become a copy of another target creature until end of turn, except it's 1/4 and has "This creature can't be blocked."
Few think to look past a familiar face and a friendly smile.
Whenever a player casts a spell, counter that spell unless that player pays {X}, where X is the number of cards in all graveyards with the same name as the spell.
Target opponent reveals the top card of their library. Cerebral Eruption deals damage equal to the revealed card's mana value to that player and each creature that player controls. If a land card is revealed this way, return Cerebral Eruption to its owner's hand.