In this week's Fringe, called "The No-Brainer," Olivia and the scoobies got to investigate their most cyber opponent yet: A pop-up window that turns people's brains to goo! Spoilers ahead, weirdos.

While I enjoy the overarching conspiracy plot in Fringe with the Pattern and Massive Dynamic, I think some of the best episodes are devoted to what sometimes derisively get called "monsters of the week." If you can come up with a weekly monster that's cool enough, it makes for excellent television (as X-Files and Supernatural have demonstrated many times over). And this week's monster, a 657-megabyte file that liquifies people's brains, was creepy and funny all at once.

We begin by watching an unwary teen clicking on a pop-up window that appears on his computer bearing the words "What's that noise? Click here." I swear clicking on a pop-up has become the "opening the door to strangers in hockey masks" of the 2000s. Why does the kid do it??? I think basically so that we can watch the weird images and remember the movies The Ring and Videodrome with great satsifaction.

After the kid's brain is liquified by the file, several other people suffer the same fate. But not before Walter can revel in cups of liquid brain and Olivia can once again tangle with evil internal investigations white dude Harris. Also, my prediction last week that Olivia's visiting sister and niece would be in danger came true immediately. The third near-victim of the evil pop-up was Olivia's niece, who barely avoided sneezing her brains out of her nose.

Unlike most of our bad guys, this week's monster-maker wasn't part of the Pattern or some other vast underground science conspiracy. He was just an out-of-work hacker with a vendetta against people he thought had wronged him: A boss who fired him, an ex-wife, and a used car salesman whose death wasn't ever explained (or was it? did I miss something?). He's invented this multimedia file that contains some kind of hand-wavey audio component that vibrates on a frequency that makes brains literally fry. Which doesn't explain why people are only affected if they LOOK at the file, since it would seem that all they'd have to do is hear it. But don't worry about that, because Walter is making funny jokes about Darwin and syphilis.

Olivia and the scoobies easily track our file-sharing killer to his (of course) underground warehouse lab lair. This is thanks in part to yet another underground science friend of Peter's who says things about megabytes and didn't seem to know about Google maps.

The pacing and gory brain stuff were terrific - this was a simple whodunnit episode done well. Perhaps the biggest flaw here was the slightly tedious rehashing of the conflict between Olivia and Harris from last week. Harris is some DHS mucky-muck who Olivia once helped to jail for sexually assaulting women. Now he's on a vendetta against her and the whole Fringe division, which he keeps saying is a "misallocation of FBI resources" for reasons he never really articulates. He says the division is "rogue" despite the fact that they always solve their cases and seem to be working within the FBI. Anyway, he spent a lot of time telling Olivia that she sucked, and she had to make her frowny face while ignoring him.

Towards the end of the episode, Olivia's boss Broyles finally steps in and tells Harris that if he fights Olivia he's fighting Broyles - there's going to be a three-letter-agency manager smackdown. I must confess that this whole subplot is a little boring and feels like a red herring. Harris isn't part of the Pattern and his character is so two-dimensional that he might as well live in the book Flatland. Get rid of him already and give us more menacing Massive Dynamic or Jones or something.

A subplot that did actually work in the episode was Walter confronting his past. The mother of Walter's former lab assistant gets into contact with him so that she can get some closure on how her daughter died: In a fire that started in Walter's old lab. Peter resists letting her see Walter, imagining that it will send the old mad scientist into a tailspin or breakdown. But Olivia convinces Peter to let Walter face up to his pre-insane asylum past, and we get a pretty touching scene where Walter talks to the grieving woman about her daughter. Then Peter gets drunk and goes over to Olivia's house to do his smokin' Pacey routine and say he's sorry.

I'll bet you a dime bag that he's going to wind up dating Olivia's sister. That's my guess.

Until next week, kids, ferchrissake don't click on a goddamn pop-up window.