The diary forgotten on the moon.
[Diary: one hour on the moon]
Dear Diary, I've been banished to the moon after the fight me and my sister had. I was just so angry! It wasn't fair, why did ponies have to sleep through my night? Some ponies even resented it! It was just not fair!
[Diary: one day on the moon]
Dear Diary, well I thought it over yesterday and I figured that this was stupid. Regular ponies unlike me and my sister need sleep, and since during the day the sun was out they could work more efficiently than they would during the night, and during the night they would rest to have energy for the day. I bet my sister has figured out that I learned my lesson and is bringing me back home, yesterday was really boring.
[Diary: three days on the moon]
Dear Diary, Why didn't my sister get me yet, I bet she thinks my punishment should last for a week, in four days I'll be back in Equestria with my sister again!
[Diary: one week and a day on the moon]
Okay, maybe I'm grounded for a month, I may have destroyed a couple building before I was exiled so maybe 'Tia just needed me to lay low for a while
P.S. hey I started marking the weeks I've been here on a wall of a cave I've been sleeping in as a joke!
[Diary: one month on the moon]
I'm going to stop with the Dear Diary now, it's not like anypony is going to read this but you and me, my sister did not get me today, maybe discord got out of his stone prison and 'Tia is having a hard time with him without me. That's why she doesn't have time to teleport me back!
[Diary: three months on the moon]
My sister hasn't brought me back yet, surely she knows I learned my lesson by now and that my punishment has been going on long enough!
[Diary: six months on the moon]
I get it now! Ponies are mad at me and does not want my sister to bring me back, so 'Tia is just waiting for everypony to cool down before releasing me from this prison. In one year I'll be out of here!
P.S. It's really lonely on this rock, why did I pride myself on making it again?
[Diary: one year on the moon]
Diary, I'm scared, it's been a whole year and my dear sister has not even showed a sign of bringing me back, maybe she isn't going to bring me back, nonsense! My loving sister would never let me endure such a harsh punishment!
[Diary: eight years on the moon]
I forgot the reason about why I was so angry, I think I wrote it on a earlier date on this book. I'm starting to remember me not being in this... form before.
[Diary: 53 years on the moon]
I'm so stupid! I should have just kept my mouth shut! I hate this soulless rock! I hate the argument I had with my sister! I hate my stupidity! so stupid. stupid. why am I so stupid!
[Diary: 503 years on the moon]
Oh Diary! I thought I lost you! After my last entry I accidentally threw you and you went into the dark side of the moon, but after all this time I found you!
[Diary: 703 years on the moon]
I'm just going to end it all. I'm going to kill myself, I'm just hurting too much. I don't care anymore. Good bye diary, good bye sister.
P.S. ARGHH my stupid sister weakened my powers by sending me here! I can't even hurt myself in this state, why sister, why have you forsaken me!
[Diary 999 years on the moon]
There are so many lines on the wall, it would be suicide to count them all, but that's all I do these days. I remember why I am in this form now. I'm going to destroy my sister when I get back home and shroud Equestria with internal darkness! muwahahaha! Just one more year and I will regain enough strength to teleport to Equestria, I just need to watch for those blasted elements this time.