Bismuth Mindrender

• WOTC Official Reminder Textofficial rules
  Menace — This creature can't be blocked except by two or more creatures.

• WWizards of the Coast2024-06-07
  Official Ruling
  A card with devoid is just colorless. It's not colorless and the colors of mana in its mana cost.
• WWizards of the Coast2024-06-07
  Official Ruling
  Devoid doesn't affect the color identity of the card for the purposes of the Commander variant. For example, while Abstruse Appropriation is colorless because it has devoid, its color identity is still white and black, and it can't be included in a Commander deck where the commander's color identity doesn't include both white and black.
• WWizards of the Coast2024-06-07
  Official Ruling
  If a spell you cast this way has in its mana cost, you must choose 0 as the value of X when casting it.
• WWizards of the Coast2024-06-07
  Official Ruling
  Other cards and abilities can give a card with devoid a color. If that happens, it's just the new color, not that color and colorless.
• WWizards of the Coast2024-06-07
  Official Ruling
  Devoid works in all zones, not just on the battlefield.
• WWizards of the Coast2024-06-07
  Official Ruling
  If you cast a spell for another cost "rather than paying its mana cost," you can't choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the spell has any mandatory additional costs, those must be paid to cast it.
• WWizards of the Coast2024-06-07
  Official Ruling
  If you choose not to cast the card, it remains in exile.
• WWizards of the Coast2024-06-07
  Official Ruling
  If a card loses devoid, it will still be colorless. This is because effects that change an object's color (like the one created by devoid) are considered before the object loses devoid.
• WWizards of the Coast2024-06-07
  Official Ruling
  You choose whether or not to cast the exiled card as Bismuth Mindrender's triggered ability resolves. If you do, you do so as part of the resolution of that ability. You can't wait to cast it later in the turn. Timing restrictions based on the card's type are ignored.

Rulings via Scryfall