Prompt: Write a short story about a man who discovers a magical portal

The man was walking down the street on a busy day, when he saw a large, green portal in the middle of the road. He was curious as to what was behind it, so he walked through it. He found himself in a vast field of grass, surrounded by a beautiful blue sky. He could see a large, orange sun in the sky. He began to walk towards it, admiring the scenery around him. Then, he noticed the large, green tree in the center of the field. He walked towards it, and as he got closer, he could see that it was made of light. He reached out his hand to touch it, and a bright light filled his body, and he fell to the ground, unconscious.