Nightscape Familiar

• WWizards of the Coast2004-10-04
  Official Ruling
  Can never affect the colored part of the cost.
• WWizards of the Coast2004-10-04
  Official Ruling
  The generic X cost is still considered generic even if there is a requirement that a specific color be used for it. For example, “only black mana can be spent this way”. This distinction is important for effects which reduce the generic portion of a spell's cost.
• WWizards of the Coast2004-10-04
  Official Ruling
  This can lower the cost to zero, but not below zero.
• WWizards of the Coast2004-10-04
  Official Ruling
  If this card is sacrificed to pay part of a spell's cost, the cost reduction still applies.
• WWizards of the Coast2004-10-04
  Official Ruling
  The effect is cumulative.
• WWizards of the Coast2004-10-04
  Official Ruling
  The lower cost is not optional like with some other cost reducers.
• WWizards of the Coast2022-12-08
  Official Ruling
  A spell you cast that’s blue and red costs less, not less.
• WWizards of the Coast2022-12-08
  Official Ruling
  Activating the ability creates a replacement effect that acts like a shield, replacing the next time Nightscape Familiar would be destroyed that turn. This shield works against effects that try to destroy Nightscape Familiar or lethal damage that would be dealt to Nightscape Familiar.
• WWizards of the Coast2022-12-08
  Official Ruling
  Nightscape Familiar can regenerate even if it isn’t in combat, it’s already tapped, or it’s undamaged.
• WWizards of the Coast2022-12-08
  Official Ruling
  You can activate the regeneration ability even if Nightscape Familiar isn’t at risk of being destroyed.

Rulings via Scryfall