Fringe Connections

The anti-gravity osmium bullets from "Os" were used as a weapon against the Observers and Loyalists in "An Enemy of Fate".

Mark Young's colleague is wearing a butterfly pin, possibly prompting the subject of his hallucination.

The flower glyph can be seen on a door in the pocket universe.

Bell was unwell and needed oxygen in Olivia's memories in "Momentum Deferred" which could be because he had lymphoma as Nina revealed in the alternate timeline in "Brave New World (Part 1)".

When Walter explains that his red/blue lensed glasses were created by his friend from Washington, Doctor Jacoby, he's referencing the television show 'Twin Peaks' which also had an eccentric man of science, Doctor Jacoby, who wore red/blue lensed glasses very similar to Walter's.

The apple glyph can be seen as Olivia and Shapeshifter Charlie fight in the alley.

The End-of-Dayers targeted the Orpheum Theater in "The Day We Died", a soft spot from when Olivia and the other Cortexiphan subjects crossed over to get Peter in "Over There (Part 1)".

Walter's pose as he listens to the Mozart Requiem is a reference to the iconic Maxell tape advertisement from the '80s.

A seahorse pattern can be seen in the toxin's molecular structure.

In "Black Blotter" Walter had a vision of his scuffle with Nina at Reiden Lake from "Peter" and later recalled other memories from that day.

Peter's grave says he died when he was 7.

A butterfly can be seen painted on the side of a white trash can.

A butterfly shadow box like those seen in "The Dreamscape" was seen in Walter's storage vault in "The Bullet that Saved the World".

Peter's shared dream state with September looks like an observation deck.

A frog can be seen outside the entrance to the daycare center.

Agent Jessup was relating season 1 Fringe cases to Bible verses in "A New Day in the Old Town". In "Nothing as it Seems", creatures can be seen on something resembling Noah's Ark.

Olivia pulled up a list of the frozen heads found in S02E04 'Momentum Deferred' and they were all marked with "2E204", a reference to the episode in which they were stolen.

The leaf glyph can be seen as Olivia and Shapeshifter Charlie fight in the alley.

Walter used the same neural halo in "The Box" as he used on the child in "Inner Child".

The briefcase contained photos of Walter.

A hand can be seen on the wall when Olivia and Peter attack the Observers and Loyalists.

In "6:02 AM EST" Walternate trapped Fauxlivia in the same cell as Olivia was kept in in "Over There (Part 2)".

The episode opened in "Manhatan", seemingly a typo but actually signifying this was an alternate Manhattan.

The apple glyph can be seen on the backrest of a chair in the lab.