A series of strange disappearances in Pennsylvania attracts the attention of the Fringe team and leads them underground. Walter also tries to recreate Olivia's accident using frogs and Charlie tries to find out how much she remembers.

The episode was rated 7.85 from 1200 votes.

As animal rights activists ransack a laboratory, they get more than they bargained for when one of the caged “animals” unleashes a ferocious appetite. Leaving grotesquely mutilated dead bodies in its wake, the scientifically engineered beast with the body of a lion, claws of an eagle, fangs of a viper, skin of a rhinoceros and tail of a serpent attacks Charlie. With Charlie’s life on the line, Walter must come face-to-face with both his past and the beast.

The episode was rated 7.84 from 1163 votes.

Olivia, along with Peter and Walter Bishop, investigates the strange death of a woman who had an even stranger child. The woman was pregnant for only hours, yet the baby she birthed was fully developed - and also aged eighty years in the span of a few minutes. Olivia asks Nina Sharp of Massive Dynamic for help.

The episode was rated 7.82 from 1808 votes.

After a cargo ship runs aground, the shoreline becomes littered with bodies hosting a giant squid-like creature. The Fringe team descends upon the scene to examine the bodies and discovers that the mysterious organisms are actually giant parasites. As the investigation unfolds, Walter heads back to the lab while Olivia, Peter and Broyles race against time when they realize the case has ties to a threatening organization.

The episode was rated 7.82 from 1079 votes.

Human beings are reduced to ash statues and Broyles realizes that the same person responsible murdered five other persons four years ago... a case that he never solved.

The episode was rated 7.80 from 1097 votes.

The team investigates a woman that re-appears after weeks of being missing with a rare disease. She also inexplicably causes pain and death to the people she meets. During the investigation, dangerous level of radiation are detected. Walter obsesses about cotton candy; Peter strikes a deal with Nina Sharp; and a truth about Olivia is discovered.

The episode was rated 7.79 from 1385 votes.

Following an unexplained attack involving hideously deformed humans, the Fringe team visits the small town in upstate New York to uncover leads surrounding the bizarre case. When it's determined that these deformed people have managed to hide themselves for a while and they'll do just about anything to keep it that way.

The episode was rated 7.75 from 1062 votes.

Olivia, Walter and Peter are called in to investigate the death of a car salesman who was found in a pool of "goo," exactly like another man across the country. When Walter discovers that the "goo" is brain matter, the trio tries to figure out how the killer can liquefy human brains. As the deaths pile up, the investigation reveals a common thread linking the victims together in an unthinkable manner. Meanwhile, Olivia is horrified when the case places a loved one in harm's way

The episode was rated 7.75 from 1207 votes.

After a teenage girl is pronounced brain dead, her mother takes her off life support, but when doctors operate quickly to remove her organs, the deceased girl shockingly awakens screaming an alphanumeric code. Equally as perplexing as her resurrection is that she is now somehow able to speak Russian and possesses classified information only a high-ranking soldier would know. While the girl's mind-bending condition intensifies, Walter dusts off some old lab videos and hypothesizes the unthinkable, sending Olivia and Peter to investigate the bewildering case in an original. (This is a season 1 un-aired episode)

The episode was rated 7.63 from 1053 votes.

While Walter deals with some very upsetting news, he tells Olivia's niece, Ella, a fairy tale that includes musical performances by Olivia and Agent Broyles.

The episode was rated 7.21 from 1024 votes.