For Spectral Matron, do you need to choose the target and set it aside as pending before the opponent can react to the trigger?

Ruling: When you play Spectral Matron, you select the target unit from trash when adding the trigger to the chain (because playing a card from trash is a targeted ability), but this does not create a pending item. You only pay costs and actually play the unit when the effect resolves.

Sequence:

• Play Spectral Matron and its "when you play me" trigger goes on the chain
• Select which unit from trash to target when adding the trigger to the chain
• Opponent can now react to the trigger on the chain
• When the trigger resolves, pay additional costs and play the unit from trash

Nuances:

• The "pending" state applies to items pending to be added to the chain (like cards played during resolution of another effect, such as Promising Future)
• Spectral Matron's trigger goes directly on the chain and is not a pending item
• Target selection happens when adding to chain, but actual playing happens on resolution