Behrman, a character in the short story "The Last Leaf" by O. Henry, spent his night in a heavy storm to make his masterpiece.

Explanation:
Behrman was a struggling artist who lived in the same building as two young women, Sue and Johnsy. Johnsy had fallen ill with pneumonia and became convinced that she would die when the last leaf fell from a vine outside her window. Sue tried to reassure Johnsy, but her belief in the leaf became so strong that she grew weaker each day.

Behrman's Motivation:
Behrman, upon hearing about Johnsy's condition and her belief in the last leaf, was deeply moved. He was known in the building as a kind and helpful man who was always willing to lend a hand. Behrman was also an aspiring artist who had never achieved success in his own work. However, he had a deep love and respect for art.

The Stormy Night:
One night, as a fierce storm raged outside, Behrman made a decision. He went out into the storm to protect the last leaf from falling. Despite his age and frailty, Behrman braved the elements and took shelter near the vine outside Johnsy's window. He stood there for hours, enduring the rain and wind, determined to save the leaf.

The Masterpiece:
Sadly, Behrman fell ill himself as a result of his exposure to the storm. Sue and Johnsy discovered him the next morning, weakened and unable to get up. They brought him inside and cared for him, but it was too late. Behrman had contracted pneumonia and his condition worsened rapidly.

Behrman's Sacrifice:
As Behrman lay on his deathbed, Sue and Johnsy noticed something remarkable. The last leaf had not fallen from the vine outside the window. It had remained steadfast, clinging to the branch despite the storm. Behrman had inadvertently created his masterpiece, sacrificing his life to give hope and inspiration to Johnsy.

Conclusion:
In conclusion, Behrman spent his night in a heavy storm to protect the last leaf from falling, ultimately sacrificing his life to inspire hope in Johnsy. His act of selflessness and dedication to art serves as a powerful lesson in the story, highlighting the transformative power of art and the depth of human compassion.