I Don't Know Anymore
Pertaining as to who or what this thing was, Jesus and Lucifer found the answer quite simple, being beings of supreme absolute power and everything in between. There was no questioning it. This was Prince Big MacIntosh.
"Are you the Princess of this fairly Equine based estate?" Lucifer asked, walking up to Big Mac and stroking his big, strong, red wings. "Such a strong equine you must be. I see you working a lot in your life, no?"
"Eeyup," Big Mac said, then Jesus slipped through the devil and took Big Mac to a hillside, where he got to see under the drop water splashing and crashing against the base. It was like music to his ears as the birds kawed and the waves swung.
"Big MacIntosh, you know, that fallen angel is a liar," Jesus told him. "I tell you the truth, nothing beneficial comes from ye who lies to gain a false security."
"Eeyup."
Lucifer took the alicorn away and stood upon a cloud in the sky, and he gave him a view of all the places and kingdoms in the world. The strong, powerful Griffin Republic, the Dragon Clique, the Bear Summit, and the Seapony Caverns. Lucifer gave to himself a sly smile as he thought about how to manipulate Big Mac. "I can give you all these kingdoms and places to be in the crease of your hoof... why take only Equestria? Why not the entire world?"
"A man... a stallion... a being should not feast on power alone, Lucifer," Jesus told the fallen angel as he pushed him gently away from Big Mac. "I suppose you know where you went wrong with that."
"A God, a Being like you has no need for lowly ponies," Lucifer growled at the Prince of Peace, of whom he was utterly disgusted and repulsed by. "And especially to these creatures, as they have no need for a god when they possess magic strong enough to bend space and move celestial bodies."
Big Mac merely looked at the two and sighed. "Eeyup."
"Is there truly an answer to the question of life?" Lucifer said to Big Mac, who nodded his head.
"Eeyup."
"And we need not to ask you on your standpoint as we can already read your heart," Jesus said, transporting himself and Big Mac away from the fallen angel, who pursued them yet again. Jesus paid no attention to the pursuer, but gave his full attention to the stallion. "I know... but do you know?"
"Eeyup."
"You truly desire a simple life. A life of apples and orchards, is that what you desire?"
"Ee--"
"Wait a minute, Big Mac," Lucifer said, trying to step closer, but a fierce, lion like glare from the Son of God stopped him right in his tracks. "You obviously cannot want a simple, lackluster life of mere apples and fields! You can help so many with a kingdom, and servant after servant preparing food for not only your kingdom, but you as well. Think about it. Do you want simplicity? Or power?"
Jesus turned Lucifer away and the fallen angel went into hiding once again. Jesus looked to Big Mac and smiled. "He who follows me shall never go hungry. I leave you will one simple command, and that is to buck apple trees. Do you accept?"
"Eeyup."
Big Mac awoke from under a tree, under which he was taking a quick nap. He had next to him a diary titled, "Simple". Within this diary, he wrote a short entry,
Dear Princess Luna,
the dreams are getting weirder and weirder.
I can't keep doing this...
I think I'll give up the experiment.
With that, the entry was over. The message was sent to Luna via magic, like in Twilight's scrolls or Sunset Shimmer's book. Instead of going to Princess Celestia, these letters instead went to Luna.
After waiting for several minutes, Big Mac was interrupted from watching the clouds stroll past when he heard the book twinkling, and Luna's letter to reply to his had finally come. He opened the book to read what was inside of it.
I urge you to try the potion again, for one last time.
Please Big Mac, we are making such good progress. I need to know what these two beings mean...
Why they act the way they do. Where did they come from?
Not even Tia knows, and Discord was stumped when I asked him as well.
You do have some potion left do you? Do not worry, I will connect to your dream from here, but I probably won't be able to interfere.
If anything different happens, document it down and send it again. I will see it, but I only want to know how it makes you feel.
It won't lead you to insanity, as it didn't do that to Tia and I, but our dreams weren't as vivid as your's.
We need you.
With love, Luna.
Big Mac sighed and looked for the potion which was in a clear bottle. There was only a pinch left, but quantity did not matter. Only the quality did. He took one last look at the farm, the barn, Applebloom and the Crusaders in the distance, the sky, the sun, and the birds flying around him. A couple of crows perched on the branches of the trees above him, and it made him really uncomfortable. He wanted to say "Nope", but Princess Luna was so nice. And beautiful. Her flowing, twinkling blue mane, and her dark coat with her lovely flank and cutie mark. He truly fell deeply in love with her, and he could not bear to say no to the mare of his dreams. He promised to himself he would come back, but he figured he would write a letter to Luna first explaining his feelings...
"Nope." Not enough time. He would do it when he got back.
Big Mac awoke to see the two beings with him again. His eyes shifted from left to right, and he stood in his throne and stepped down.
"Shall we introduce ourselves?"
"Eeyup."
"I am Jesus of Nazareth. Son of God. The Messiah of Earth and all of Mankind."
"And I am Lucifer, the fallen angel of Venus, the morning star. Some say I am evil, but I fare to disagree."
"Eeyup."
Jesus took Big Mac to the field which was the Apple family orchards. He smiled and took in a deep breath of the air. "You know, you will forsake me. You will turn me over and walk with my enemy. Bu surely you have been forgiven."
That was too new, but as Jesus faded from sight, Big Mac found that Lucifer had grabbed him and pulled him into a portal leading back to the throne room of the Canterlot Castle. Big Mac, feeling disoriented, found his mind to now be completely blank. He saw his diary beside him, though, not knowing what it was, he picked up the book and read a message within it.
I have been holding my feelings back, and I cannot anymore. You are the nicest, kindest stallion I know. You are such a hardworker, and you never turn down the opportunity to help another pony in need. I adore that. I just must say, I love you. I should not have put such a burden on you, and I should not have sent you back in after you told me how you thought you couldn't go on anymore. I love you, and I hope you can read this before you go.
With True Love... Luna
Lucifer approached Big Mac as he read the letter, and noticed how confused the stallion looked. He chuckled before asking, "Luna? Do we know a Luna at all?"
Big Mac sighed and closed the book, putting it down and walking past Lucifer to his balcony. "Nope."
A few days later, as it rained outside, Big Mac felt compelled to go out for a fly. The dirty, abused ponies of below cowered in fear and ducked in cover when he flew over them. He really did not care. He descended when he reached a grave yard, and approached a tombstone which had the name "Luna" engraved on it. Also on it was, "She went hoping to find her love. Nopony knows if she found him."
"Sure ain't talkin' 'bout me," Big Mac said lowly, as the thunder crashed and he found in his mind one image of Luna smiling at him as he took the first sip of the potion three years ago. He dismissed the thought as merely an overactive imagination, and then turned from the gravestone, tears streaming down his face.
"Are you sorry for doubting her? You truly understand now how important she truly was to you... don't you now?"
"...Eeyup."