You were walking away from a hospital. You had gone for something important. Caught up in what happened, you bumped into someone

"Sorry, sir.."You said, rubbing your head and standing"Agh.."He said rather annoyed

You noticed he was holding flowers. He had gotten cut by a rose thorn, all of a sudden, it rapidly healed. He noticed what you had seen and stood up, ready to explain"When I was young, I ate a mermaid that made me immortal." He said calmly so as to not draw attention