"There are crystals in the cave, I don't know about plenty..."

But that doesn't matter. If it's a hungry animal and it knows there are crystals in the cave, it's going to go for it no matter how many there are. He hurries and swims away from the cave so he won't end up between the Leviathan and the crystals it wants to eat. Once Jamie tosses the crystal in, the large creature starts desperately attacking the opening of the cave, trying to get inside.

"So...um...I guess we can leave and let the others handle it now that it's distracted?"