You could try to signal for help, or just wait around. You have supplies enough to last out here for at least a day without getting too hungry or banged up. But even if you do... are you sure the Zhark can't get inside the grotto? You'd feel a lot safer if you had some kind of weapon.

Beyond a very small pocket knife, there isn't much you have to really fend off an attacker, especially not one so big. You banish any ideas of being able to kill the Zhark; Swall folkloric heroes never killed them anyway. Stealing from a God and slipping away unseen or archetypal tricksters tricking beings far greater then them dot your mythical past. You figure that the fire corals are your best bet. But you can't just stab the Zhark with a coral, you won't be able to get close. You want something at arms length... maybe a spear?

Spears are an archaic weapon. Despite their importance in your prehistoric societies and mythologies, even artwork and burial traditions often included spears or the imagery of spears; in modern times they have mostly been forgotten. Nobody learns how to fight with them, as they are an inferior weapon. Nobody glorifies mastery or warriors who once used spears; as the socio-economic factors creating the conflicts that lead to their use have now been solved and abstracted. Conflict of roving bands of Swall for valuable resources and mates have been evolved into resource collection and acquisition through capitalism and assets; bloodless conflict. It's a superior system; though you really don't know much about that. You just think you'd rather have a gun in this situation!

Except... Spears have stuck around in your culture for one small thing. Your species nuclear weapons. Much in the same way spears were used as they are effective in water and on land, and are especially useful to keep away larger and more dangerous predators; so to were the first nuclear weapons so named as spears. Many early Swall scientists and thinkers thought that the cosmos might be similar to an ocean, and may also be filled with creatures. Your people know now this is true; as space is filled with alien races, some belligerent and violent. As such, a global defense network of space-launching nuclear missiles were created as soon as your technology was capable of making weapons of such strength; envisioned as being your new species "spears" pointing out of your homeworld, threatening anyone who came too close looking to prey upon the young Swall. You suppose it worked too; as the Jaxtians were so afraid of them they forced your government to disarm their nuclear weapons and enter an agreement. You have autonomy while they colonize and watch the stars above you. Even to children your age, it is clear that the Jaxtians and their Hegemony have a certain advantage over the Swall, but putting your spears away as a sign of good faith is a generally agreed-upon good choice that makes peace between the races more likely.