The series Supernatural has its fair share of absolutely terrifying episodes. It wouldn't be the show it is without them, after all. Still, to alleviate the gore and horror, the show manages to sneak in light-hearted content from time to time.
Whether it's Dean's many movie references, Sam's more gentle approach to the people they help, or recurring gags like the fact that the brothers are often mistaken as a couple, the show has its moments. Early on, even in Season 2, it was apparent that Supernatural would have plenty of gore and humor in store, and its episodes proved that.
Funniest: "The Usual Suspects"
Sam and Dean are arrested while investigating a case, and while Dean is stuck thanks to his record, Sam manages to escape. The comedic aspect of this episode mostly has to do with Dean, who has an attitude while being held in custody, asking for cheeseburgers and providing the kind of information a dating site would be looking for while being videotaped for a "confession." He infuriates the officers effectively, much to the amusement of audiences, while Sam hurries to solve the case before someone else dies, and gains the trust of one of the officers, who has become involved in the supernatural case, which proves beneficial as she later lets the brothers go.
Scariest: "Hunted"
Sam finds out the horrible words his father said to Dean regarding Sam in his last moments, and runs off. While Dean searches for him, Sam goes looking for other psychic children like him. With Ash's help, he locates one that has recently passed away and Sam goes to investigate.
Sam soon finds himself hunted not by the supernatural, but fellow hunter Gordon Walker, whom he and Dean encountered before. Gordon, knowing Sam is one of the psychic children, has decreed in his own mind that Sam is a danger to humanity and seeks to kill him, and kidnaps Dean to lure Sam into a trap. Luckily, Sam was warned by another psychic, but still, to be considered a monster had to be horrifying for Sam, just as it was for Dean.
Funniest: "Everybody Loves A Clown"
Though the brothers are still reeling from the loss of their father, there's still time for humor, particularly in the form of Dean who teases Sam regarding his phobia for clowns. Turns out, according to this episode's villain, Sam's right to be terrified of clowns. Not only that, but the Winchesters are shown up by Jo and Ellen who hold guns on them in their bar until they figure out who Sam and Dean are; Jo even managed to punch Dean so precisely he couldn't even see. Plus, the episode introduced the memorable character of Ash, a guy with a mullet who was asleep on a pool table initially.
Scariest: "What Is And What Should Never Be"
After he's attacked by a djinn, Dean winds up living an entirely different kind of life, working as a mechanic, dating a beautiful girl and finding his mom alive. While his dad is dead and he doesn't have the same close relationship with his brother, Dean is nonetheless thrilled.
However, as the anomalies add up, Dean is forced to confront the heartbreaking truth: he's really dying, and the djinn has given him the fantasy life in the meantime. Dean finding out that the djinn was playing with his mind had to be scary, and even scarier, he had to make the choice to stay in his happy life and die, or go back to his real life and confront the reality he didn't want to be in.
Funniest: "No Exit"
The Winchesters find Jo and her mother arguing, and end up taking Jo's case. However, Jo shows up in Philadelphia anyway to help, and forces the brothers to lie to her mother regarding her whereabouts. Jo's banter with Dean is especially uproarious as she tries to prove herself despite Dean's doubts, and the boys end up rescuing her from the ghost and sealing him in permanently, once Dean steals a cement truck. Though, that uncomfortable silence with Jo and her mom in the car definitely had to be a long drive on the way back.
Scariest: "Croatoan"
The brothers head to a small town in Oregon to investigate after Sam has a premonition, and endure a horrifying reality soon after arrival. They find themselves trapped, unable to contact anyone outside of town and unable to leave because of the townspeople, who have become hostile and violent. This is due to the threat of a virus, which turns its victims violent.
It's terrifying, really, the thought of being stuck in such a town, with a possibility of being infected. Sam is eventually infected, forcing Dean to make some tough choices for a moment before they find that Sam is actually immune. Stranger still, the infected people later vanish, leaving the town deserted. Definitely creepy.
Funniest: "Tall Tales"
Sam and Dean are stumped by their current case, and they're at each other's throats, bickering like siblings do over who did what. When Bobby shows up to help, he discovers who's really behind all the pranking and sets the brothers straight, making them look like kids in the process. Though, it does help them solve the case and eventually make up, though it's not the last time they'll be seeing the trickster. It's hilarious to watch Sam and Dean fight the way they do, especially since it's not something audiences see often with the Winchesters.
Scariest: "In My Time Of Dying"
The season premiere finds Dean comatose and in danger, as a Reaper awaits him. Sam desperately tries to find a way to bring his brother back, even communicating with him through a Ouija board, and angrily argues with his father, believing John is still focused on the hunt and not Dean.
The scary thing is, John is actually preparing to make a deal with the demon Azazel and follows through, and while it saves Dean's life, it kills John and leaves his sons broken, especially Dean who now has new information about Sam from John.
Funniest: "Folsom Prison Blues"
The funniest aspect of this episode in its entirety is how well Dean adapts to prison life, which both annoys and worries Sam. They intentionally allow themselves to be captured so as to help out an old friend of their father's, who is a prison guard that explains there's been strange things happening at the prison he works for. The two work hastily to solve the case and escape before they're extradited thanks to Agent Henriksen, and just when it looks like Henriksen and his agents will catch the boys in the act of digging up a grave, it turns out they're in the wrong cemetery. Priceless.
Scariest: "All Hell Breaks Loose (Part 1)"
The first half of the season finale brought a ton of scary moments. Sam's abduction, finding the Roadhouse burned to the ground, Sam's discovery that he has demon blood, and the fact that Ava had been killing off the other psychic children in succession in order to survive since her own abduction months before were all awful. However, all of these terrifying events lead up to the most horrific event of all: Sam's death. At the time, it was the first time Sam had ever died on the show, and audiences had no idea what to expect afterwards, seeing Sam die in a heartbroken Dean's arms. Audiences had no idea what Dean would do, but they'd soon learn in the second half.