Stranger Things fans spot Easter egg for final season that the Duffer Brothers placed in Season 1

Warning: this article contains spoilers for season 5 of Stranger Things

Eagle-eyed TV fans believe that there was an Easter Egg for the finale of Strangers Things dating back to season one.

The highly anticipated finale of the well-loved Netflix show dropped on New Year's Eve and it's received a mixed response from viewers.

With the show running for the best part of a decade and it being one of the streamer's biggest and most successful series, it was inevitable that people would have extremely high hopes for the final episode — and some have been left disappointed.

One fan on Twitter went as far as branding the finale as 'the worst finale in TV history since Killing Eve & Game of Thrones'. Yikes.

Other reviews have been less critical, however, with the Stranger Things finale boasting 7.9/10 on IMDb at the time of writing.

For those who have seen the final and the penultimate episodes, you'll know what The Abyss looks like and how the Mind Flayer took center stage in it.

In light of Henry Creel's (Vecna) love of spiders, the Mind Flayer looks very spider-like and boasts several legs. The Mind Flayer was already its own entity before Henry turned evil, but it was him who shaped the ancient entity into the monstrous figure we see throughout Stranger Things.

Before the beast battled it out with the likes of Eleven, Nancy and Dustin, it was somewhat embedded into the ground of The Abyss and had its legs up in the air to kind of resemble a tree.

Since these episodes have aired, sleuth Stranger Things viewers have shared a theory that The Abyss and the Mind Flayer's final form were teased way back in the first season.

In season one, Mike has a The Dark Crystal movie poster in his bedroom and some believe that this was a nod to The Abyss years in advance.

Some believe that this scene 'foreshadowed' the finale (Netflix)

Sharing a clip of this moment from season one against the scene where Holly sees The Abyss for the first time in season five, one TV fan penned in a YouTube Short: "So you are telling me we already saw this in S1?"

The video has sparked hundreds of comments from fellow Stranger Things fans. One person said: "And suddenly the theory of everything being Mikes imagination is kinda making sense...That's literally in his room."

"NO WAY IT WAS ALL CONNECTED FROM THE START," wrote another.

"The cracks could also mean something," suggested someone else. Echoing similar sentiments, a different person penned: "IT HAS THE YELLOW LIGHTNING AND CRACKS TOO OMG."

"That's a poster of The Dark Crystal movie ... It was foreshadowing the ending," added a separate fan.

What do you think?