Season 4 of Pretty Little Liars has been chocker-block full of “OMG” moments - and we can only imagine the summer finale will add to the number. As we anxiously await the summer’s climactic episode, here are the top 15 moments from Season 4 that had us yelling “OMG” at our television screens.

Wilden is Dead!

The answer to the much-discussd “What’s in the Trunk?” was a bit of a let down (spoiler: it was a dead pig), but also grossly fortuitous. As the Liars drive past Wilden’s swampy police cruiser the following morning, they see a dead body covered on the pavement. The wind blows the tarp covering the corpse to reveal its identity to the Liars and us: someone killed Wilden!

Someone Tries to Kill Mona!

Following the events of the Season 3 finale, Mona has declared herself Team Liars, but the Liars are less enthusiastic about drafting a new team member. In Season 4, Episode 2: “Turn of the Shoe,” a masked figure hides in the back of Mona’s car and tries to choke her - with the Liars standing only feet away! They manage to save their frenemy, but not without consequence. The car tries to run the Liars down, and Em ends up with a busted shoulder.

Emily Smashes Into the Pool Wall!

To swim through the pain of her injured shoulder, Em pops more pills than are strictly necessary. They cause her to go woozy during a swim meet, misjudge the distance of the pool wall, and slam her head into it. It is seriously hard to watch - Paige wasn’t the only one holding her breath as Emily was pulled out of the water and rushed away on a stretcher.

Melissa ‘Fesses Up!

Though Mona claims that Wilden and Melissa were both dressed as The Queen of Hearts on that fateful Halloween train, we aren’t really sure we can believe her - until Melissa admits to Spencer that she was the other costumed figure that night. Melissa also spills that Wilden was blackmailing the “B” Team, and that he was the one to set the Thornhill Lodge on fire. Jury’s out on how much we can trust Melissa, but the scene was effective in convincing us (at least for now) that Melissa is trying to protect her little sister.

Spencer Finds the Secret Room!

There’s nothing creepier than stumbling upon secret rooms with retro radio sets and a connection to your dead friend. This is exactly what happens to Spencer, who inadvertently finds a hidden room in a Cicero College sorority house. The room contains the phone Alison had called so much the summer of her death. Who was staying in the room, and why was Alison calling him or her remains to be seen, but this still qualifies as a serious “OMG” moment for its creep factor alone.

Hanna Is Caught Gun-Handed!

While Spencer was busy uncovering secret rooms, Hanna was busy trying to bury the weapon responsible for Wilden’s murder. Hanna’s frantic race through the woods outside the sorority house, her attempt to dig into the dirt, and her police capture were classic PLL. Extra points for getting to see Spencer and Emily’s reaction to their friend being led away from the sorority party in handcuffs.

Ashley Marin is Arrested for Murder!

This moment was a long time coming, but it was no less effective. When the police show up at the Marin house to arrest Ashley for the murder of Wilden, it is predictable - but it is also heartbreaking and concerning. We (and Hanna) know what “A” is capable. As Ashley was led away, we couldn’t help but wonder if it was for good.

Spoby Sees Shana in Ravenswood!

Spencer and Toby’s entire visit to Ravenswood was one big “OMG” moment. The town was as spooky as it was unhelpful. But the biggest surprise came when Spencer spots Shana at the cemetery gathering. What was Shana doing in Ravenswood? And why were all of those people hanging in the cemetery? We’re still waiting on these answers...

“A” Drives Into Emily’s House!

The Liars aren’t safe anywhere. We know this, but sometimes it is easy to forget. “A” literally smashes that false wall of security when she drives a car into the Fields house, almost killing Pam. There have been some seriously scary moments in PLL, but watching “A” turn Emily’s living room into rubble? That ranks among the scariest.

Mona Confesses to Wilden’s Murder!

Mona is one of the most erratic characters on the show - it’s hard to figure her out. But when she confesses to Wilden’s murder to keep Hanna from doing it herself, we were both surprised and intrigued. Did Mona really do it to help her former best friend? Or does she have other motives? Whatever her reasoning, this was an awesome way to end a less-than-exciting episode.

Jenna Almost Drowns!

We’re not Jenna’s biggest fans, but we couldn’t help but freak out when Emily finds her floating facedown in the Rosewood lake. The most effective PLL scares come when we’re enjoying some happy friend moments and, though Emily’s surprise birthday party wasn’t exactly the best in the history of suprise birthday parties, we hardly expected it to delve into attempted-murder territory.

Red Coat’s Crawl Space is Discovered!

The DiLaurentis house was creepy enough without it’s very own Red Coat hideaway. The discovery that someone (i.e. Red Coat) has been living in the DiLaurentis’ basement crawl space was eerie, but the moment when Em turns out the lights only to discover that Red Coat has drilled holes into the ceiling to peer at/listen to what’s going on above sent chills down our spines.

Wren Knows About Red Coat!

We’ve always been suspicious of Wren, but Season 4, Episode 10: “The Mirror Has Three Faces” was the first time we got hard evidence that this doctor is up to no good. Episode moments when we see him creeping on Haleb or discussing “loyalties” with Mona were interesting, but the episode-ender that sees him coloring a Red Coat into his “feelings photo” had us “OMG”-ing.

Ezra Isn’t Malcolm’s Father!

There are spooky “OMG” moments, and there are sad “OMG” moments. The discovery that Ezra isn’t Malcolm’s biological father falls into the latter category. This moment is played out over the space of a few scenes, but Ezra’s valid accusation that Maggie let Ezra fall in love with the little boy knowing he wasn’t his father was the most heartbreaking of “OMG”s.

Cece is Red Coat?!

Season 4 has been full of Cece reveals - though she hasn’t been present at most of them. The end of Season 4, Episode 11: “Bring the Hoe Down” was the biggest. Inside Ezra’s apartment, Ezra is telling Aria all about the Maggie/Malcolm mess while, outside, a black-hoodied Cece Drake is listening into the entire thing. We’re still not convinced Cece is Red Coat, but this moment was definitely “OMG”-worthy.

Do you agree with our top 15 “OMG” moments? Are there some we missed? Sound off in the comments below!

Catch the Pretty Little Liars Season 4 summer finale on Tuesday, August 27, 2013 at 8 p.m. ET/PT on ABC Family.

Credit: Celebified Photo: Pretty Little Liars Season 4 Summer Finale Spoilers: Is Ali Alive? Will Spoby Ever Have a Date Night? — Exclusive