As one of Netflix's most successful and talked about original series, 'Stranger Things' made an incredible impression following its debut in 2016, and this past week returned for its second season on the streaming service. With all nine episodes of the season dropping at the same time, fans have been binging to get up-to-date on the storyline being told but one particular episode - the seventh of season 2 - got some of the fan base questioning exactly why the decision had been made to take such a different direction for 45 minutes.

David Harbour stars as Sheriff Hopper in 'Stranger Things'David Harbour stars as Sheriff Hopper in 'Stranger Things'

This is where you should probably turn back if you don't want spoilers regarding the seventh episode of 'Stranger Things', season 2!

In the episode, viewers saw Eleven (Millie Bobby Brown) come face to face with a girl from her childhood - another youngster that had been experimented on in Hawkins Lab and who had been branded with the number eight. Gifted with the ability to get into people's minds and make them see whatever she wanted them to see, she would immediately showcase her skills to her 'sister' Eleven, harking back to the brief encounter viewers had with her in the first episode of season 2.

The pair would then go on to track down and almost kill one of those who worked at Hawkins Lab - the man who responsible for destroying the mind of Eleven's birth mother. It was a dark episode that had hints of 'American Horror Story' and 'The Purge' mixed into it, and not everybody was a fan.

Speaking with EW, co-creators The Duffer Brothers explained of the episode: "Whether it works for people or not, it allows us to experiment a little bit. It’s important for Ross and I to try stuff and not feel like we’re doing the same thing over and over again. It’s almost like doing a whole little other pilot episode in the middle of your season, which is kind of a crazy thing to do. But it was really fun to write and cast and work on."

Whether or not the episode will yield more like it in the future remains to be seen. Fans now think it could have acted as the perfect set-up to a spinoff series following Eleven's 'sister' and her gang, but nothing has yet been confirmed. It's going to be very interesting to see how this one develops...

More: 'Stranger Things' Creators Already Writing Season 3

'Stranger Things' seasons 1-2 are available now to watch on Netflix.