Murakoshi Shinta is a student prone to wild delusions. He has kept this hidden all this while, living his gloomy and mundane life. One day, a tentacled alien parasite takes over his penis. Murakoshi complains to it that he is unable to walk around outside, what with his groin exposed, but the alien assures him that no one will notice as it has the ability to cloud people's minds.

What would be the top 15 anime series that you would have on your must-watch list? (Don't include any mainstream/major anime like Naruto, One Piece, Fairy Tail, etc.)

Not all non mainstream anime I’ve watched are good.
I don’t think i can name 15 top non mainstream anime that will be worth your while, thus i will try to give a list of 10(Don’t think i will reach 10 either).
According to me, the top anime that are a must watch other than the major animes are 1 Attack on Titan-No anime beats this anime in suspense.
Very less romance and comedy.
Only action and suspense.Very few don’t like it but those many who like it are crazy about it.
(like me) 2 My Hero Academia-Not a single boring episode.
Funny, good bgm and an interesting plot.This anime has huge potential to become the number 1 anime in future, like Naruto was.
So this will be the anime that takes Naruto’s place as number 1 anime in the rest of the world(One piece might give a heavy competition, but One piece was always more popular in Japan and not that much in the rest of the world). 3 Code Geass-Thrilling plot.
Has the best ending of all the anime I have seen.
You will be at the edge of your seat till the end!!.
Good suspense, but still not as much as attack on titan though. 4 Deathnote-This anime is a subset of Code Geass, but still it is recognized as good(even better by some) as Code Geass.
I love the bgm and the mind battle is very intense. 5 One punch man-Hero who defeats every villain in a single punch.This may seem like a dead end in a general plot, but actually One Punch man’s plot starts from there.
These guys(manga authors) developed a ‘very difficult to develop’ type plot in the best way possible.
One of the best comedy anime.
While the plot moves very slowly, it is interesting.
Especially the latest manga chapter was awesome…can’t wait for it to get animated. 6 High School DxD-Warning, this is an echhi type anime.
But has a superb and intense story line.
The original version was a light novel.
The novel became so famous that it got anime adaptation.
And Anime turned out to be very good as well and so manga was made from the anime.
It exceed the expectations of many.
Watch it.….you won’t be disappointed. 7 Erased-A very emotional thriller.
And that animation quality is out of this world..A very good thriller for just 12 episodes!!!! 8 Mirai Nikki(Future Diary)-This is one of the best under rated anime.
Good plot and the last twist was very awesome!!!.
Worth watching once. 9 Akame ga Kill-Worth watching once.
A funny and interesting plot.
But ending was a bit bad in the anime.
But the manga was very good.
This manga has one of the best endings…So i would suggest to read the manga. I haven’t watched Steins gate, Seven deadly sins, Neon Genesis Evangelion and Fate series.
These anime have a chance of making into this list.