This is a Commander format that is inspired by the card Dragon's Egg.
Deck building: Uses the same criteria as Commander for deck construction.
Special Rules:
You start the game with 10 life. After shuffling up your deck and having an opponent cut the deck, count off the top 30 cards, keeping them in order and unseen. These 30 cards are your starting deck.
Put the remaining cards aside, but keep them in order.
You will play the game as a normal commander game now with a few exceptions. When you die or would lose the game, you remove completely from the game any cards in your hand, graveyard or library. Now return the rest of your library that was removed at the beginning of the game. This is your new library consisting of 67-69 cards depending on commanders and companions. Set your life to 30. If it was your turn, your turn ends and play resumes. This is called Hatching.
If a player would use any infinite combo ,or instant win, that would win the game for them, if any players are still in their Egg form (The first 30 card library and 10 life) they hatch and play continues. The infinite combo stops once the players hatch, but if the combo can be restarted, the player can still win the game outright.
If the player playing an infinite combo to win is still in Egg form, they hatch and play continues.
Players only lose if they have already hatched and a condition exists that would cause them to lose (reduce life to 0, have to draw on an empty library, someone's instant win condition, etc)
Set up: Select 10 effects to use during the game. It can be actual enchantments, instants or sorceries or custom effects you create. The effects can be one time effects like Wrath of God or it can be a persistent effect like Cather's Crusade. You cannot respond to these effects happening. All persistent effects only last one round.
Play:
1: Play as normal, except every 2 rounds you flip a coin. If it is Heads, Chaos Ensues. Roll a D10. Depending on the roll, a new Effect takes place.
2: Roll happens after the last player in the round completes their turn but before the first player starts their untap step.
3: Effects do not use the stack and you cannot respond to them.
Current League Effects:
1: Bontu's Last stand: Destroy all creatures. Lands you control don't untap during your next untap step. (Land portion of the effect applies to ALL players).
2: Cather's Crusade: Whenever a creature enters the battlefield under your control, put a +1/+1 counter on each creature you control.
3: Summon: Knights of Round (Each player gets a copy of this saga. 1st chapter happens for each player immediately. All other chapters happen as normal.) If players still have a Summon: Knights of Round on the battle field, remove all copies and reroll Chaos.
4: Glen Elendra - Plane: At end of combat, you may exchange control of target creature you control that dealt combat damage to a player this combat and target creature that player controls. (No Chaos)
5: Dance with Calamity: Shuffle your library. As many times as you choose, you may exile the top card of your library. If the total mana value of the cards exiled this way is 13 or less, you may cast any number of spells from among those cards without paying their mana costs. (Each player in player order resolves this effect)
6: Planar Chaos: Whenever a player play a spell, that player flips a coin. If he or she loses the flip, counter that spell. (No Upkeep trigger)
7: Pyxis of Pandemonium: Once on the player's turn, that player exiles the top card of his or her library face down. When a new Chaos effect is rolled, Each player turns face up all cards he or she owns exiled with Pyxis of Pandemonium, then puts all permanent cards among them onto the battlefield.
8: Do or Die:Separate all creatures target player controls into two face-up piles. Destroy all creatures in the pile of that player’s choice. They can’t be regenerated. ( Resolved in player order. Each player gets a copy that targets the player to their left.)
9: Cryptolith Rite: Creatures you control have "T: Add one mana of any color."
10: Warp World: Each player shuffles all permanents he or she owns into his or her library, then reveals that many cards from the top of his or her library. Each player puts all artifact, creature, and land cards revealed this way into play, then puts all enchantment cards revealed this way into play, then puts all cards revealed this way that weren't put into play on the bottom of his or her library in any order.