Prismatic

Prismatic is a casual constructed Magic: The Gathering format for fans of big, fun, five-color decks.
Each Prismatic deck must contain at least 250 cards, including at least 20 cards of each color. If a card is multicolored, you choose which of its colors to count it as for this purpose. For example, a red-green card can count as one of your 20 red cards or one of your 20 green cards, but not both.
Prismatic games use the "big deck mulligan" rule. If the first player's initial hand of cards has 0, 1, 6, or 7 lands in it, that player can mulligan and draw a new hand of 7 cards (rather than the usual 6). If the player does, each other player has the option to do the same, regardless of how many lands are in their hand. After that round of mulligans is over, the next player has the option to take a big deck mulligan. If that player does, it would again allow everyone else to take one too, and so on. Once all the big deck mulligans are over, each player may mulligan as normal (drawing one fewer card each time).
==Magic Online==
Prismatic was a DCI-sanctioned casual format on Magic Online. Construction rules and a special mulligan rule were the same as described above. Prismatic was based on the Classic format. All sets and Promotional cards were allowed. Official support for prismatic ended on November 11 2015https://magic.wizards.com/en/MTGO/articles/archive/magic-online/magic-online-announcements-october-27-2015
==Banned==
Ante and manual dexterity cards are banned as well as the following cards:http://www.mtgoacademy.com/deckbuilding-rules-and-banned-restricted-lists/#9
==References==
Category:Magic Online