M:tG card similarity search
3R · Enchantment
At the beginning of each upkeep, count the number of permanents. If the number is odd, until end of turn, red creatures get +1/+1 and whenever a player taps a Mountain for mana, that player adds an additional {R}. If the number is even, until end of turn, red creatures get -1/-1 and if a player taps a Mountain for mana, that Mountain produces colorless mana instead of any other type.
| Name | Mana | Type | Text |
|---|---|---|---|
| Hedron Matrix | 4 | Artifact — Equipment | Equipped creature gets +X/+X, where X is its mana value. Equip {4} |
| Keening Banshee | 2BB | Creature — Spirit | Flying When Keening Banshee enters the battlefield, target creature gets -2/-2 until end of turn. 2/2 |
| Contamination | 2B | Enchantment | At the beginning of your upkeep, sacrifice Contamination unless you sacrifice a creature. If a land is tapped for mana, it produces {B} instead of any other type and amount. |
| Silverskin Armor | 2 | Artifact — Equipment | Equipped creature gets +1/+1 and is an artifact in addition to its other types. Equip {2} |
| Doubling Cube | 2 | Artifact | {3}, {T}: Double the amount of each type of unspent mana you have. |
| Unnatural Endurance | B | Instant | Devoid (This card has no color.) Target creature gets +2/+0 until end of turn. Regenerate it. |
| Cruel Feeding | B | Instant | Strive — This spell costs {2}{B} more to cast for each target beyond the first. Any number of target creatures each get +1/+0 and gain lifelink until end of turn. (Damage dealt by a creature with lifelink also causes its controller to gain that much life.) |
| Riding Red Hare | 2W | Sorcery | Target creature gets +3/+3 and gains horsemanship until end of turn. (It can't be blocked except by creatures with horsemanship.) |
| Livaan, Cultist of Tiamat | 2R | Legendary Creature — Dragon Shaman | Whenever you cast a noncreature spell, target creature gets +X/+0 until end of turn, where X is that spell's mana value. Choose a Background (You can have a Background as a second commander.) 1/3 |
| Tainted Strike | B | Instant | Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) |