Can you respond with a reaction (like flipping a hidden unit) when a temporary sprite token triggers at the beginning phase to maintain battlefield control?

Ruling: Yes, you can react to the sprite token's beginning phase trigger by flipping a hidden unit to maintain control of the battlefield and get a hold point.

Nuances:

• If you play a hidden card that creates another temporary token in response to the trigger, that new token will stay until the next turn because the beginning of turn trigger has already occurred and won't happen again this turn.