Mythic Rare is the rarest of the rarity types. They can be recognized by the shiny orange color of the edition, on the right middle of the card.
Details[]
A Mythic Rare card.
In a booster pack, you get one rare. The chance of opening a mythic rare in a booster pack is not very large, but if you do open one, it will replace the rare.
The first mythic rares appeared in the Shards of Alara block. Mythic rares were invented partly because, out of the 50 to 100 rare cards in a set, some rares were considered too good to stay with the others. They were mostly invented however to drive sales of packs. There are generally 10 to 15 in a set.
Most mythic rares have abilities which are stunning and crushing. Cards like Hellkite Overlord and Godsire can blow away your opponents. However, many mythic rares have abilities that are considered too expensive or too "niche" to be considered playable.
Also note, most mythic rares are not usually cheap to cast (one exception is Dragonmaster Outcast). While they are usually a good deal for the immense power you get from casting it, they can be quite expensive at times! (Just take a look at Emrakul, the Aeons Torn or Progenitus - expensive, but look at the power.)
Also, most mythic rares are usually fairly easy to trade, much because of their rarity. Wurmcoil Engine, all of the Eldrazi, Darksteel Colossus, Gaea's Revenge, Progenitus, and especially Thrun, the Last Troll are examples of very tradable, playable mythic rares. The mentioned Progenitus considered by many the most powerful creature that exist, because it has protection from everything; however, its mana cost makes it a nearly unplayable card (2 mana points of all different colors).
Rarity of Mythic Rares vs. Previous Rares[]
There is about a 1 out of 8 chance per booster pack to get a mythic rare instead of a rare. The reason is when printing, usually 15 out of 121 cards on a sheet are mythic rare instead of rare, giving us the 1/8 approximation. In such printings, there are two of every rare, and just one of each mythic rare, resulting in each mythic being twice as rare as a standard rare card.
Here is a table for odds of getting a specific rare or mythic rare card in a single booster pack:
| Series: | # of Rares / MRs: | Odds: |
|---|---|---|
| Ravnica | 88 | 1:88 |
| Guildpact | 55 | 1:55 |
| Dissension | 60 | 1:60 |
| Coldsnap | 40 | 1:40 |
| Time Spiral | 80 | 1:80 |
| Planar Chaos | 50 | 1:50 |
| Future Sight | 60 | 1:60 |
| 10th Edition | 121 | 1:121 |
| Morningtide | 50 | 1:50 |
| Shadowmoor | 80 | 1:80 |
| Eventide | 60 | 1:60 |
| Shards of Alara | 53 Rares 15 Mythic Rares |
1:60.5 1:121 |
| Conflux | 35 Rares 10 Mythic Rares |
1:40 1:80 |
| Alara Reborn | 35 Rares 10 Mythic Rares |
1:40 1:80 |
| Magic 2010 | 53 Rares 15 Mythic Rares |
1:60.5 1:121 |
| Zendikar | 53 Rares 15 Mythic Rares |
1:60.5 1:121 |
| Worldwake | 35 Rares 10 Mythic Rares |
1:40 1:80 |
| Rise of the Eldrazi | 53 Rares 15 Mythic Rares |
1:60.5 1:121 |
| Magic 2011 | 53 Rares 15 Mythic Rares |
1:60.5 1:121 |
| Scars of Mirrodin | 53 Rares 15 Mythic Rares |
1:60.5 1:121 |
| Mirrodin Besieged | 35 Rares 10 Mythic Rares |
1:40 1:80 |