Fringe

Olivia is escorted to the interrogaton room where she finds Mr. Hughes.  She wants to know why he wasn't watched.

During the autopsies, Walter discovers that Mrs. Hughes had Lupus, an auto-immune disease that makes it almost impossible to maintain a pregnancy.  He also becomes quite upset every time somebody mentions the little boy's grave.

Lansdale.  Sheriff Go-lightly is winding crime scene tape around the Hughes house.  He doesn't notice the ground rising up behind him, a la Bugs Bunny.

Olivia and Broyles talk in a parkade, where Olivia overhears a phonecall from a man who hasn't even entered the parkade.  He asks why she discharged her weapon.  Misfire, she says.  Olivia also suffers from some kind of visual hallucination/flashback. 

Walter's investigations reveal scorpion DNA.  He hypothesizes to Peter and Astrid that Dr. Hughes dosed his unborn son with scorpion DNA, which is highly resilient, in order for it to survive his mother's womb.  This would also account for the paralytic agent (scorpion venom) and the tunnelling under the coffin.  Olivia hears this conversation from across the lab.

Back to the sheriff.  He finally notices the tunnelling under the ground when he's standing beside his car.  But instead of getting in the car,  he just stands there and watches whatever-is-under-there come at him.  Obviously, he's not a Kevin Bacon fan.  He gets sucked under without leaving a trace.

Olivia and Peter arrive at the house and notice the abandoned cruiser.  As they search the house for Sheriff Go-lightly, Peter finds a papered-over door leading to an abandoned nursery.  Olivia finds a door which leads to a cellar.  They find a loose brick in a wall and pull it out, revealing a tunnel.  Olivia, in the tradition of bad horror movies everywhere, sticks her head into the hole to see if the monster is there.  She sees the partically-masticated body of the sheriff.  Gollum didn't attack her then; it waits and grabs her from behind after she stands up and pulls her into the hole.

With a deadly grip on her bruised shoulder, Gollum pulls her down the tunnel.  Peter dives in after her but cannot wrestle her away.   Eventually they stab the scorpion baby with the femurs of one of its victims.  Gollum tries to tunnel away but comes up under the cruiser, which collapses the tunnel, falls in, and crushes Gollum to death.

Olivia and Not-Charlie ruminate on the case.  It seems Hughes was trying to catch the monster; he was digging traps all over his property.  Not-Charlie asks her how she is doing and if her memory has returned.  She says no; perhaps she doesn't want to remember.  Not-Charlie says that perhaps a trip to an alternate universe is worth remembering.

Back at the lab, Peter goes through his old fishing box and digs out a night-of-desireable-object lure.  He tells a story of how a boy saved up and bought it in the hopes that he and his father could go fishing.  Walter doesn't understand the "boy and father" part and assumes Peter got it from a friend.  He asks if he can go fishing too, and a humoured Peter tells him he's welcome to come.

Olivia experiences another hyper-sensitive flash.  She hears the individual bubbles in her bath pop.  Then she hears a fly on the wall, then her neighbours, the cars in the street and noises from farther and farther out.  The cacophony is deafening.  Suddenly, it stops.

She goes to the address listed on the note Nina Sharp gave her.  After a weird test of some sort, she finds Sam Weiss, who asks her if the headaches have started yet.  No.  They will, he informs her.

Not-Charlie has returned to the Selectric shop.

Not-Charlie:  Target visited other side but remembers no details.  Please advise.

Mirror: Unacceptable.  If she can't remember on her own then do something to help her.