Luckily for Gale, the surprise does indeed involve light. She squeezed his hand reassuringly, noticing the forced tone, before she used her chakra to light up her hand with a green glow.

The glow from her hand reflected off the crystals in the rock around them, creating what looked like a green, starry sky above them. Once she was sure that the light had the desired effect, she glanced back to Gale for his reaction.