When Spectral Matron's ability lets you play a unit from trash 'ignoring its cost', do you still need to pay additional costs like Cruel Patron's 'kill a friendly unit' requirement?

Ruling: When cards say "ignoring costs" they refer to the base costs in the top left only. Additional costs still need to be paid.

Sequence:

• You play Matron, resolve it, and put it on board
• Matron's "when played" ability triggers, targeting a unit from trash, and goes on the chain
• You don't pay for the targeted unit yet at this point
• Opponent can respond to the trigger
• When the ability resolves, you play the targeted unit and must pay any additional costs
• If you cannot pay the additional costs (e.g., no unit to sacrifice), the ability fails

Nuances:

• "When you play" is the same as enters the battlefield; there is no separate "cast" concept in this game
• The unit from trash is not "pending" when the trigger goes on the chain - it only gets played during resolution