Bard prepares to fire his trusty black arrow at Smaug's weak spot as it attacks Lake-town
"The dragon swooped once more lower than ever, and as he turned and dived down his belly glittered white with sparkling fires of gems in the moon - but not in one place. The great bow twanged. The black arrow sped straight from the string, straight for the hollow by the left breast where the foreleg was flung wide. In it smote and vanished, barb, shaft, and feather, so fierce was its flight. With a shriek that deafened men, felled trees, and split stone, Smaug shot spouting into the air, turned over and crashed down from on high in ruin."
- The Hobbit: Fire and Water