For Jinx (red), is the 'discard two' effect a cost that must be paid, or a normal 'when you play' triggered effect?

Ruling: The discard two is a triggered ability, not a cost. It triggers after Jinx has been played, and you do as much of it as you can based on your hand size.

Sequence:

• Play Jinx
• The 'when you play' trigger occurs
• Discard up to 2 cards (discard 1 if you only have 1 card in hand, discard 0 if you have no cards)

Nuances:

• If it were a cost, the card would say "as an additional cost to play me, discard a card"
• The "when you play me" wording indicates it's a trigger that happens after the unit has been played