Can a hidden Foxfire on Battlefield A be played as a reaction to target units moving to Battlefield B?

Ruling: You cannot play Foxfire as a reaction to a move, and even if you could play it, hidden cards can only target units at the battlefield they are hidden at.

Nuances:

• You can technically play the hidden card, but it can only target the battlefield it's hidden at
• Foxfire cannot be played in reaction to a move action