It's technically 9 days but I don't care since this is the better title.
I wrote 100k in a short time span and that's all that matters.
Now, how did this come to be? For that, we have to set the scene.

I am not very productive during the longer school days, and my mind cannot really write during the later stages of the day.
It means basically nothing on the weekends since I'll just get up early but I have next to no progress during the weekdays. Not fun.

This is where I then got the most devilish idea. School vacations. I had one of those coming up last week. 
Since I had ultra productivity during weekends, one mega-weekend would surely equal a lot of productivity.
...
Right?

One of the main worries going into this challenge was proper consistency.
I am a person who does not use his time wisely and I knew for a fact that I have considering binging all of House MD the moment I was done with school Friday afternoon.
I had 9 days to spend on myself. I wanted to write during it but doing nothing likewise called to me.

I knew I would stay consistent during the first few days since I have that going for me, but actually maintaining that would be hard. 
That's why I figured out a cheat. I could write extra during those first few days.

With 9 days to use, I would have to write a minimum of 11.12k every day to keep up. On Sunday, the second day of the challenge, I wrote 20,000 words in the span of 24 hours. It was mentally painful to do but it kept me in the green by a landslide.

My ability to do 20k in one day actually kept my mood up very high. Slight megalomania, thinking back on it, but it most certainly worked. Monday and Tuesday, honestly.
However, that was about the time that my body decided that my being able to accomplish it all too easily wouldn't be fair.
Wednesday morning, I woke up coughing.

Being fully honest, I wanted to end it right there. I felt like shit, my body hurted in weird ways, and a fever was starting up.
However, I decided that succumbing to bodily weakness was for weak people so... just said no. Sadly, sickness doesn't understand the concept of consent.
While I wrote on Wednesday, like nothing was wrong, it came back to bite me Wednesday night.

I guess it also counts as Thursday morning since I had about 3 hours of sleep during those twelve hours. My body, looking at my arrogance, decided that my wings needed to melt. I was forced out of my keyboard's clutches and into bed. While I wrote 0 words during that entire day, I must attest that the soup was great.

Friday morning I am still feeling like shit. Not as much, however, through the pain of a lot of meds and a very desperate need to start writing again.

The other three days were about the same. I had three days of free time and 38k words to write. It was only through that initial burst of 20k words that I wasn't screwed outright but I couldn't let myself relax just yet. During those 3 days, I wrote 12.6k words every day without hesitation. It was hard, it was gruelling, and my mind was wishing for a coma by the end, but the fact is that I reached the hecking end.

Through the span of 9 days, eight of which were spent actually writing, I had written 100k words. Good stuff.

(BTW: I have been noting down my daily WC since the start of the summer vacation. Can you spot when I started this marathon?)