Check the misterious structure

You pass the final patrol using your invisibility spell. The corridor opens into a vast chamber with torches, and there glows a mountain of gold, jewels, and... A big red dragon egg that looks like a majestic jewel.

The ruby scales pulse with inner fire, it's beautiful.

But the gold isn’t just loot. Something is moving and looks at you, it's a small grey goblin armed with a magic sword covered by shadows and a chain. He's nude and his voice resonates inside your mind. "I'm the treasure goblin, and you will be my anal whore... relax and spread wide little girl."

Disgusted and angry, you prepare a powerful spell, but you start to think about the egg, you don't have more time, so you must act now.

You can use a fireball, it's a powerful spell, but the damage to the egg could be irreversible.
You can use an ice knife, but the goblin is small and you can miss but the egg will not suffer any damage.