Credit: Annette Brown/The CW © 2011 The CW Network, LLC Photo: Bonnie and Jeremy Exchange a Look in Season 2, Episode 17: "Know Thy Enemy"

We love those moments on The Vampire Diaries that make us gasp, pause, and rewind — and Episode 17, “Know Thy Enemy,” was chock full of them. Here are the five scenes that left us with our jaws agape this week.

5) Isobel rocks Jenna’s world
“Hello Elena, it’s nice to see you again,” Isobel said. She looked through the doorway past Jenna who stood understandably stunned. “Again?” Aunt Jenna asked her niece. Forget the insult that followed (“So you’re the woman who’s dating my husband”), with that last five-letter word Isobel broke Jenna’s heart by outing her boyfriend as a stone-cold liar and her niece as the ultimate betrayer (until later in the episode, of course). We didn’t blame her when she tore off to lock herself in her bedroom (though she could’ve used a detour at the fridge for some ice cream — not Chunky Monkey. Too many memories). After all, Aunt Jenna uprooted her life to take over as the world’s worst guardian so her niece and nephew could have a sense of normalcy. Of course, we all know that things aren’t a fraction of what they seem in Mystic Falls. But Aunt Jay doesn’t. And, just like that time Katherine compelled her to stab herself, this truth cuts. Deep.

4) Congratulations: it’s a boy you already know
Speaking of Alaric… Just when we thought Isobel had caused enough trouble for the vampire-slaying history teacher, she stops him on the street to apologize for what she did and for what she was about to do. “He’s all yours,” she said as she turned away. One second later, Creepy Wizard Dude telepathically knocked Alaric out and took him to be sacrificed to the Original, Klaus. We’ve spent all season wondering who Klaus would be and what he would look like. We never expected him to take the shape of one of our own. So when Alaric stood in front of Katherine with the gaze — and accent — of a centuries-old bloodsucker, we stopped breathing for a sec.

3) Totally bewitched
We’ve said it before, and we’ll say it again: When it comes to her friends, Bonnie is a ride or die girl. That was never more true than when she fearlessly walked into the abandoned mansion to gather the energy of 100 murdered Salem witches. The harvest was painful. Apparently, the spirits couldn’t just hook a witch up. They had to hit her with wicked whispers then make her relive their experience of being burned alive. “Bonnie? Bonnie! You’re scaring me here,” Jeremy said as his new boo screamed bloody murder. No kidding.

2) Now that’s a sunburn!
We’ve gotta give it to her. Isobel sure knows how to make an exit. After Creepy Wizard Dude freed her from the spell that caused her to backstab everyone she cared about, she decided to make things right with Elena by apologizing. “I’m so sorry, Elena,” she said. “I was such a disappointment to you.” Then she stepped onto the grave her human parents still visit each week, snatched off her magical necklace, held up her arms, and proceeded to burst into flames. Some things you never forget. We’re pretty sure watching the birth mother you hate burn to death is one of them.

1) Matt manhandles the truth
Apparently noble Matt Donovan is a pushover no more. Much like Aunt Jenna, he spent the last year in the supernatural dark. But all it took was one glimpse of the vamp face of his girlfriend Caroline for him to turn undercover agent for the establishment. Dosed with verveine, he went to the blonde bloodsucker pretending to be willing to listen and give their vamp-human relationship a chance. Minutes after she poured her heart out to him, he walked down the street, hopped in Sheriff Forbes’ squad car and spilled his guts. “I went over there, and I got her to tell me everything,” he said. “Thank you Matt,” Sheriff Forbes replied. And when Matt said he felt like Caroline had died, her mom then said the two saddest words of the night: “She did.” Sob!