The answer is: Sling and stone

1 Sam 17:49-50 - "So David prevailed over the Philistine with a sling and with a stone, and struck the Philistine and killed him." David killed Goliath with the stone and then "visibly" killed him so the crowd could see he was dead by cutting of his head with Goliath's sword.

When you think of David and Goliath, the impressive imagery of an underdog facing a giant springs to mind. David's weapon of choice—a sling and stone—highlights a significant cultural aspect of ancient warfare: skill and strategy often triumphed over brute strength. A sling could accurately hurl stones at incredible speeds, turning a young shepherd into a formidable adversary.

Moreover, the story of David uses this pivotal moment to illustrate profound themes of faith, courage, and cunning in the face of overwhelming odds. It's fascinating to note that shepherds in ancient Israel would have trained for such encounters, sharpening their skills to protect their flocks from predators.

The act of decapitating Goliath symbolizes a finality and also directly ties back to showing the might of Israel's God—David’s victory resonated with the Israelites, reminding them that faith involves aligning with a divine purpose that transcends ordinary measure.

This narrative reverberates throughout many cultures and can be seen as an inspiration for those facing their own struggles against "giants" today. In broader storytelling, this battle against the overwhelming opponent rings similar to many tales of heroism, underscoring the unexpected turns of life where the smallest pebble can bring down a towering foe. So, whether metaphorically or literally, it reminds us that great things can come from humble beginnings and that seemingly trivial choices can lead to monumental outcomes.