"You see my watch?" asked Santa Claus, slightly tapping the golden wristwatch.

"Yeah, I'm not blind."

Santa Claus chuckled, "I know, I know." Then, he started to explain, "You see, this wristwatch can allow you to travel in time, as well as stopping it. It's a powerful device, and the only one of its kind, although there are some strict rules you have to follow when you activate it. For example, you cannot use it to go back in time before your birth."

"Why?" grunted Misha. "It's boring if you can. Not at all appealing. I mean, I would really like to visit the Seventeens, or watch a real fight between samurais, or talk with Socrates, Shakespeare, Einstein, all those great figures. Singing a duet with Elvis would be great too. I'm a good singer, you know?"

"It sounds exciting, but you can't."

Misha pouted, taking a sip of his hot chocolate – Santa Claus had been refiling his mug now and then since they started talking, a few hours ago.

"Do you know the butterfly effect?"

"…" Misha frowned, suddenly deep in thought, before finally answering, "It's linked to a butterfly… I guess?"

"Yes and no. It's the name of a scientific theory. It is said that if an occurrence, no matter how small, happens, it can change the course of history. So, if you go back in time before your birth and what you do change your own fate, resulting in you never being born, then how could you go back in time in the first place and make those changes? It's a paradox that the device won't allow."

"Oh… And what's the link with the butterfly?"

"Let's not talk about the butterfly."

"Oh. Okay…" Misha lowered his head, a bit depressed, and took another sip.

"Gosh, my head hurts. Keep it simple, will you?"

The man chuckled. "I will try. In short, to resolve that problem, when you go back in the past, it's your memories that travel, not your body. The device will protect those memories inside your brain, and they won't be erased even if you change the course of your life. You will remember the first timeline. Also, it cannot transfer the physical envelope because it cannot exist at the same as your younger form. I won't explain why, it's a bit complicated, but in the end, that's another reason why only the memories travel back in time."

Misha brain shut down.

Santa Claus, seeing his blank expression, added, "In a way, it's like a memory card that you transfer from a computer to another one."

"Then why can't the device do the same if you want to travel back before your birth?"

"And where will your memories go? If you are not born, then there's no receptacle available to receive them. It's already hard to adapt the memories into a younger self since the brain hasn't experimented those souvenirs, and it's simply impossible with a stranger's brain. The personality and the memories of the original host would clash with yours, and you would lose your mind."

Misha nibbled the rim of his mug. Indeed, it would be hard to keep his sanity if his memories were to mix with another one. It would become a real mess, not knowing what was his, and what was theirs.

"How about a baby?" He heard himself say.

"It also doesn't work with a new-born since the brain is not enough developed to welcome a fully grow-up mind. The brain's capacity is too limited at this age to accommodate an a.d.u.l.t's knowledge. The youngest age you can go back is around ten years old, but you will still suffer from several drawbacks, like chronic headaches, fevers, extreme fatigue, and so on."

"Well, traveling in time is going against the law of the Universe; of course you have to pay a certain price."

"Hm… Then what about a person in a vegetative state?"

"Are you sure it's a good idea to transfer your memories in a wounded brain? Moreover, there is also a question of moral integrity. Stealing the body of another to go back in time is not exactly ethical. However, the first reason for not going back before your birth is the one I told you in the beginning. The device can protect your memories if, one point in time, you are born, but if it never happens, it cannot. Your memories and self will be erased, and you will cease to exist."

"It doesn't necessarily mean that I won't be born if I'm going in the past before my birth, though…."

"But the possibility is there. You may not do it intentionally, but your actions may trigger a chain of events that leads to this situation. The device won't take any chance since it protects his owner above all else."

Misha nodded, even though he didn't understand everything and his brain felt like it was boiling. He still asked to satisfy his curiosity, "Then what about traveling in the future?"

"It's possible, but this time, your body will also be sent along with your memories, and once you travel in the future, you cannot travel in the past anymore. You can only continue to advance in the timeline."

"Why?" asked Misha, stunned.

"In one hundred years or five hundred years, and so forth, you will be dead. So, how can your memories travel in the future? In short, the body comes along with your mind so you can travel in a timeline where you do not exist, and that is why you cannot go back in time. The device can bring an organic vessel in the future, but cannot bring it back. It's also cannot send back your memories because the time of the travel would damage them. A couple of dozen years, it's fine. But hundreds, it's too long. Do you understand?"

"That's… not a good idea. The memories of different lifetimes will mix up together, and you will end up insane. In each of your travel, things will be slightly or entirely different, and your mind won't be able to keep up at some point."

"You know, my mind already can't keep up with the present talk…"

Santa Claus chuckled once again. "Don't worry; I'm sure you understand the main point."

"Yeah, I guess." Counting on his fingers, Misha started to enumerate, "Can't go back in time before my birth, the memories travel like a memory card, and if I travel into the future, then I won't be able to come back in the past. Well, except if I'm traveling in my lifetime, but that's not a good idea since I'm going to lose a few screws somewhere along the line."

"Yes, that's pretty much it."

"Didn't you say something about stopping the time?"

"Yes, I did. Traveling in time is not the only function this device has. It can also stop the time for everything except yourself. That's how I can distribute so many presents in a single night without being seen," winked Santa Claus, making Misha laugh.

'Even if the grampa is a bit senile, his delusions somewhat hold water,' thought Misha in the back of his mind.

"Do you have other interesting things? Or only the watch?"

"I've adjusted the date for the summer when you were nine. It's already a risk to send you back to such a young age, but I'm sure you will be alright. I also added a special option. If after one year you want to come back in 2019 and erased the alteration you had caused to the original timeline, then press this button," the old man pointed one of the small buttons on the side of the wristwatch before resuming, "and say, "I want to go back in 2019, December 24th, 23:59.""

With a serious expression, Santa Claus looked into Misha's eyes and added, "You won't be able to use the watch for anything else since the other options are restricted. It would be problematic if you were to play with the wristwatch without knowing what you are doing after all. Also, don't forget to bring the watch back when you reach this date in the timeline. I really need it for my work."

"Ok, ok, I will," indulged Misha, thinking that the delusion was going a bit too far, but at the same time, he felt that the old man was filled with joy with the perspective of sending him back to his mother and sister. Thus, he didn't have the heart to refute him, to tell him that time-travel machine was nothing but a pipe dream and that Santa Claus didn't exist.

"Give me your wrist," the old man hurried him, and the bartender reluctantly stretched his arm. When his fingers touched his skin, he got goosebumps all over.

"Happy Christmas Eve, Misha," said Santa Claus as he strapped the golden watch around the youth's wrist.

The bartender blinked. He never told him his name, did he? He looked at the man in dismay, swallowing back his words when he saw the clock hands stuck at 23:59. They had been talking for such a long time, yet it wasn't even midnight? Was it broken?

"Have a nice trip," said the man with a soft voice as his lips stretched slightly. A hint of sadness glinted in his grey eyes.

Those were the last words Misha heard before falling into a deep slumber.

______________

MC: AUTHOR!!!

Author: Hm?

MC: What's the damn link with the freaking butterfly?!

Author: Google is your friend ~

ML: *Sighs* It's about how the flap of a butterfly's wings can create a tornado or something like that.

MC: … And what's the link again with time travel?

ML: *Stares at the author*

Author: Don't look at me! All of my brain cells are dead after writing this chapter; I really can't explain anything anymore! QAQ

MC: Oh, so your brain broke too? °^°

MC: Hm? c:

ML: Just don't write that kind of thing if your brain can't keep up.

Author: *Pouts*