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Tear Jerker: Teen Wolf
The TV series:
The entire history of Derek Hale. All of it- most of the main cast have had bad things happen to them, but from the age of 16 onwards his life has been nothing but one tragic event after another. Meet a gorgeous girl at 16 who you fall head of heels for? Yeah, she's your teacher and you have to keep it secret, but you love her, and she seems to love you too. Only she's really a hunter using you to kill your entire family! Great home life? Happy, loving family of werewolves? Killed in a fire that you were (at least indirectly) the cause of! So you spend the next few years wallowing in misery and guilt, but it's okay, you still have your older sister... nope, she gets murdered. By your psychotic, supposedly comatose uncle, no less. And that's before the series even starts, for crying out loud...
In 3x08, we learn why Derek's eyes are blue. It's because he had to Mercy Kill his first love after the werewolf bite didn't take. Made worse by the fact that he helped set up the werewolf attack that was supposed to turn her, and that she knew Derek was some type of supernatural creature anyway, so it could have worked out.
Lydia crying over Jackson is not a happy time...
"I miss your mom."
In the latest episode, we have Stiles and his dad, the latter of whom reveals that he was fired because Stiles has stolen police property and gotten a restraining order placed against him, which didn't reflect well on the Sheriff or the county. The fact that Stiles looks ready to either break down sobbing or give his dad a hug during the conversation doesn't help at all.
Stiles: ...Dad? Why aren't you yelling at me?
Sheriff Stilinski: Because I don't want to feel any worse by having to yell at my boy.
Allison's mother killing herself to keep from being a werewolf. Made worse by how her husband having to help her to do it.
"I'll tell them that you suffered from depression. Even though, in the last twenty years, I've never once seen you depressed..."
Scott, Stiles, Jackson, and Allison fall under a hallucinogenic spell, preying on their worst issues. While Scott's issues (the loss of Allison) is the lightest, Allison fears she'll become just like her father, aunt, and grandfather, Stiles think his father blames him for his mother's death, Jackson fears the loss of his identity.
Scott's fears have more layers if you look at them. Depending on when you think it starts, part of it could be the part where Stiles walks away for seemingly no reason. Not to mention, Allison is Scott's anchor as a werewolf. Losing her could mean losing control.
Could be a case of Fridge Brilliance, back in Lunatic when he and Allison broke up, he could remember how dangerous and out of control he became when he actually lost her and that's why the fear is so much more real than before.
The backstory of the kanima's master: Dunked in a pool by the drunken '06 high school swim team (which, as he attends school with the main cast, means that it had to have been around when he was ten to twelve), suffers a near-death experience, only to be dragged out and ordered by the swim coach to keep quiet about it, even being forgotten by those who were there. Sure, he was unhinged, but you could clearly understand just what knocked him loose. This becomes worse at the ending of the episode when Matt, who is revealed to be the Kanima's master, is fleeing the police station and Gerard catches up to him and drowns him in the river, and Matt's last thoughts are of drowning in the pool. Disturbing as fuck.
Scott's mom recoiling in fear and terror when she sees him wolfed out and the heartbroken look on his face afterwards.
The Sheriff having a near meltdown upon seeing Stiles bloodied, beaten, but very much alive after his disappearance from the lacrosse field. After threatening to 'pistol whip' those responsible, he finally breaks down into tears and hugs his kid as tightly as is humanly possible. Also a Crowning Moment of Heartwarming.
The final ten minutes of Season 2, entirely, are heart-warming, awesome and tear-jerking all in one for both Jackson and Lydia. Let's recap. Lydia knows that she needs to find Jackson to return his house key in a symbolic declaration of her love. When she and Stiles arrive at the fight scene, Kanima!Jackson goes to attack her. Lydia doesn't flinch, and instead holds the key to him; he begins to turn back to normal. As he takes the key, Derek and Peter attack him, leaving him to die in Lydia's arms, where she tells him how much she loves him. As she lays his dead body to the ground, she begins to cry. All of a sudden, he begins to move, and he rises as a werewolf, renewed. The two finally embrace with tears in their eyes. Damn, writers, just... Damn. Because Stiles witnesses the whole thing. Remember he's been in love with Lydia for years and had actually been making some progress this season before this.
The episode in season 2 where Allison's mother is going to die Because Derek had to scratch her away from killing Scott at some underground party. She knows she's going to turn into a werewolf and she chooses to die by her own terms, with her husband helping her. The scene is so moving, especially after he'd agree to help her with her suicide note. You can clearly see that even though they're kind of manipulative and evil, they do care for each other. Also, tops to Allison's reaction when she finds out her mother died.
Another Tear Jerker moment would be at Lydia's party when everyone Is hallucinating on spiked Wolf's Bane punch. The most saddest hallucination would have to be Stiles'. After getting his dad fired from the force because of something stupid he did, and having the hallucination it was his fault that his mother died - especially since the hallucination is an angry drunk you can see the pain written all across's Stiles's face.
Season 3 episode 1. Isaac is talking with Mrs. Mc Call in the hospital, they can't contact Derek, his emergency contact. When she asks if he has another contact? He answers that is Scott.
Stiles, upon finding Heather's body. Not just in the fact that he's looking at the dead body of someone he knew, but also because he knew her because of his mother.
Isaac has several scenes in Unleashed (season 3, episode 4) that are absolutely heartbreaking.
First, he and Allison are locked in a supply closet, causing him to have flashbacks to how his father used to lock him in a freezer in their basement. He begins to have a panic attack, slams himself repeatedly against the closet door, and wolfs out, injuring Allison in the process. When Scott rescues them and gets Isaac to regain control, he looks horrified at having clawed Allison and apologizes over and over.
Later, Derek has to send Isaac away from the loft for his own safety. In order to completely drive him away emotionally as well as physically, Derek refuses to explain his motives and, when Isaac questions him anyway, throws a glass at his head in a horribly close parallel to Isaac's father in 2.02.
Isaac: Did I do something wrong, Derek?
One that pulls triple-duty as a Crowning Momentof Heartwarming and Crowning Moment of Awesome as well: A mentally battered Scott is attempting to commit suicide with a road flare and gasoline spread around his feet. He begins to tell Stiles, Allison, and Lydia about how he used to be nothing before he was bitten, how he wants to be nothing again, and how everyone would be better off with him gone. Stiles finally has enough and gives one of the most beautiful speeches in the series yet, proving that he's not just a lancer or sidekick to Scott; he truly loves his best friend with every ounce of his being and would die for him.
Stiles: Okay, listen to me, okay? You're not "no one." Okay, you're someone. Scott, you're my best friend. Okay? I need you.(choking up)Scott, you're my brother. Alright, so... (he begins walking into the gas) If you're gonna do this, you're just gonna have to take me with you then. (takes the flare and throws it away)
Boyd's death. Not only because it's accompanied by a flashback of Erica's death which shows she died trying to kill Kali but also because of how everyone reacts. Especially Derek.
Stiles' face after his father gets taken by the darach. It's the face of a kid on the verge of a complete breakdown, because as far as he knows, he's probably just lost the only other parent he had.
Doesn't help that Stiles finally told his father about all the supernatural events that have occurred thus far, with the Sheriff understandably not believing everything, and his last words to him were ''Mom would've believed me."
Ethan's description of what life was like for him and Aidan prior to them joining Ducalion's pack: They were omegas, at the bottom of the pecking order, at least in part because they couldn't control their shapeshifting ability. And they were treated horribly, until they learned from Ducalion and killed their way up the food chain. They didn't join up with Ducalion out of lust for power but literally for their own good.
Stiles' expression when he talks about his dad, who'd been taken by the Darach, especially when he starts musing to himself/Cora in the ambulance. It actually hurts to look at.
Derek still can't catch a break. His Mercy Kill turns out to be the reason Jennifer Blake is still alive, making him indirectly responsible for even more pain.
Papa Stilinski revealing the story of why he always had an inkling that something was up in Beacon Hills: As a deputy, he had to help a girl who was dying in a car accident. The girl declared, "if you want to be with her, go now", referring to his dying wife. He didn't believe her words, and he stayed with the girl until she passed away. When he went to the hospital after the fact, he found Stiles in the waiting room, head in his hands. His wife had died and Stiles was alone with her when it happened.
The end of Alpha Pact, where the main characters are about to make enormous sacrifices to save their families. It's the depressing music and fear on their faces (and possible consequences) that really sells it.
In a happy way, the ending of Lunar Ellipse, where Derek and Cora are finally okay, and don't have anything really hanging over their heads, and Derek finally gets the hell out of Beacon Hills.
The end of "The Overlooked", where Scott's agrees to join Deucalion, and Stiles is pleading with him to stay, saying that they always have a plan B, just don't go, and Scott replies "not this time".
Stiles talking with Caitlin in the hospital, about why she and her girlfriend had camped out.
Stiles: You wanted to make it romantic ...
Allison breaking up with Scott in the first season because she can't trust him.