An egg

You don't have to believe it. It could just be a good story.

"What happened?"
"You died."
"Are you God?"
"Yup."
"Oh. So what happens now? Do I go to heaven or hell or something?"
"Neither. You'll be reincarnated."
"Ah. So the Hindus were right."
"All religions are right in their own way. Walk with me."
"Where are we going?"
"Nowhere in particular. It's just nice to walk while we talk."
"So what's the point then? When I get reborn, I'll just be a blank slate, right? A baby. So all my experiences and everything I did in this life won't matter."
"Not so. You have within you all the knowledge and experiences of all your past lives. You just don't remember them right now. Your soul is more magnificent, beautiful and gigantic than you can possibly imagine. A human mind can only contain a tiny fraction of what you are. It's like sticking your finger in a glass of water to see if it's hot or cold. You put a tiny part of yourself into the vessel, and when you bring it back out, you've gained all the experiences it had. You've been a human for the last 42 years, so you haven't stretched out yet and felt the rest of your immense consciousness. If we hung out here long enough, you'd start remembering everything. But there's no point doing that between each life."
"How many times have I been reincarnated then?"
"Oh lots. Into lots of different lives. This time around, you'll be a Chinese peasant girl in 540AD."
"Wait, what? You're sending me back in time?"
"Well, I guess technically, yes. Time as you know it, only exists in your universe. Things are different where I come from."
"Where you come from?"
"I came from somewhere else. There are others like me. I know you want to know what it's like there, but you wouldn't understand."
"Oh. Wait. If I get reincarnated to other places in time, I could have interacted with myself at one point."
"Sure. Happens all the time. And with both lives only aware of their own lifespan you don't even know it's happening."
"So what's the point of it all?"
"Seriously? You're asking me the meaning of life?"
"It's a reasonable question."
"The meaning of life, the reason I made this whole universe, is for you to mature."
"You mean mankind? You want us to mature?"
"No, just you. I made this whole universe for you. With each new life you grow and mature and become a larger and greater soul."
"Just me? What about everybody else?"
"There is no one else. In this universe, there's just you and me."
"But all the people...."
"All you. Different incarnations of you."
"Wait. I'm everyone!?"
"Now you're getting it."
"I'm Lincoln? I'm Hitler?"
"And everyone he killed."
"I'm Jesus?"
"And all of his followers. Every time you victimize someone, you're victimizing yourself. Every act of kindness, you've done to yourself. Every happy and sad moment ever experienced by anyone was, or will be, experienced by you."
"Why? Why do all of this?"
"Because someday, you will become like me. You're one of my kind. You're my child."
"You mean, I'm a God?"
"Not yet. You're a fetus. You're still growing. Once you've lived every life, you'll have grown enough to be born."
"So the whole universe is...."
"An egg. Now it's time for you to move on to your next life."