Underworld Breach

• WWizards of the Coast2020-01-24
  Official Ruling
  After an escaped spell resolves, it returns to its owner's graveyard if it's not a permanent spell. If it is a permanent spell, it enters the battlefield and will return to its owner's graveyard if it dies later. Perhaps it will escape again—good underworld security is so hard to come by these days.
• WWizards of the Coast2020-01-24
  Official Ruling
  If a card has no mana cost, its escape cost is an unpayable cost, so you can't cast it for that cost.
• WWizards of the Coast2020-01-24
  Official Ruling
  Once you begin casting a spell with escape, it immediately moves to the stack. Players can't take any other actions until you're done casting the spell.
• WWizards of the Coast2020-01-24
  Official Ruling
  If a card has multiple abilities giving you permission to cast it, such as two escape abilities or an escape ability and a flashback ability, you choose which one to apply. The others have no effect.
• WWizards of the Coast2020-01-24
  Official Ruling
  Escape's permission doesn't change when you may cast the spell from your graveyard.
• WWizards of the Coast2020-01-24
  Official Ruling
  If you're casting an adventurer card or split card with escape, you choose how you wish to cast it, then pay the appropriate cost (for the Adventure, the creature, or the half of the split card you chose) plus exiling three cards.
• WWizards of the Coast2020-01-24
  Official Ruling
  If a card with escape is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.
• WWizards of the Coast2020-01-24
  Official Ruling
  If you cast a spell with its escape permission, you can't choose to apply any other alternative costs or to cast it without paying its mana cost. If it has any additional costs, you must pay those.
• WWizards of the Coast2020-01-24
  Official Ruling
  If a spell you're casting with escape has an additional cost of discarding cards or sacrificing permanents, you may exile cards discarded or sacrificed this way to pay that part of its escape cost.
• WWizards of the Coast2020-01-24
  Official Ruling
  To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as an escape cost), add any cost increases, then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was and no matter whether an alternative cost was paid.

Rulings via Scryfall

• WO
  Wizards of the Coast2020-08-03

  Underworld Breach was banned in pioneer on August 3, 2020. Therefore, we're choosing to ban Inverter of Truth, Underworld Breach, Walking Ballista, and Kethis, the Hidden Hand in Pioneer. Our intent is to dramatically reduce instances where players risk losing to a combo kill when tapping out in the early- to mid-game. Source: https://magic.wizards.com/en/news/news/august-8-2020-banned-and-restricted-announcement
• WO
  Wizards of the Coast2020-03-09

  Underworld Breach was banned in legacy on March 9, 2020. As combination decks revolving around Underworld Breach, Lion's Eye Diamond, and Brain Freeze were refined, it became clear from the rising win rates that Underworld Breach's interaction with Lion's Eye Diamond would remain problematic in Legacy going forward. Rather than allowing these decks to become a large part of the competitive metagame before likely still needing to make a change in the near future, we're choosing to ban Underworld Breach now. Source: https://magic.wizards.com/en/news/news/march-9-2020-banned-and-restricted-announcement
• WO
  Wizards of the Coast2025-03-31

  Underworld Breach was banned in modern on March 31, 2025. Mox Opal teaming up with Underworld Breach created an explosive and resilient combo deck that was notoriously resistant to graveyard and artifact hate. Between that resiliency and its explosiveness—with it being able to win as early as the first turn—we're confident that it's time to send Breach back to the underworld. Source: https://magic.wizards.com/en/news/announcements/banned-and-restricted-announcement-march-31-2025