Fringe Connections

The radioactive isotope compound from "The Cure" that caused heads to explode was used as a weapon against the Observers in "An Enemy of Fate".

Sam Weiss died 10-15 years earlier in a shootout with Observers trying to protect the radio signal relay used to locate Michael.

Butterflies can be seen in Olivia's bedroom.

Michael played the music box from "The Boy Must Live" for September after September got shot in "An Enemy of Fate".

There are 'Wanted' billboards for the Fringe team.

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

The hallucinogenic drug from "The Dreamscape" was used as a weapon against the Observers in "An Enemy of Fate" to make them think they were being attacked by butterflies.

In his dream at the end, young Peter is in bed wearing a jersey with the number 96 on it. The number 96 is the same jersey number that Joshua Jackson wore as Charlie Conway in the Mighty Ducks trilogy.

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

Walter had the Cortexiphan subjects stand in a circle around him to activate their abilities in "Over There (Part 1)" just like he did when they were children in "Subject 13".

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

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

Walter stole Bell's hand in "Letters of Transit" to gain access to Bell's personal storage unit in "Five-Twenty-Ten".

The episode ends with September going into December's apartment, apartment 513, the episode code of the next and final episode of the series.

A seahorse can be seen on the Bishops' refrigerator.

John Mosley's beanie in "The Arrival" has the 'green-green-green-red pattern' from "The Equation".

This episode reveals that there is more than one Observer. The intro sequence since the pilot episode has had a single frame that says "OBSERVERS ARE HERE".

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

William Bell had a bell on his desk in "There's More Than One of Everything". He rang it after he introduced himself. He did that to prime Olivia to receive his soul should he die in the future. Walter rang that bell in "Os" and Olivia became inhabited by William Bell.

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

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

Nina communicated with an animated William Bell in "Brown Betty". When Walter and Peter found Bell in Olivia's mind in "Lysergic Acid Diethylamide" he was animated.

All of the people in Olivia's mind wear blacks and greys because Cortexiphan subjects have a strong desire to blend in.

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