The climax of Creature Feature John goes through a kind of Body Horror only The Fly could understand, but he transforms close enough to save Margery, Nathan and Lisa from the Teenage Tick monster. Margery kills the original Tick Monster by kicking a bottle of acid (while restrained to a surgery table, no less), and John kills the Tick's creator Dr. Mangle. Followed by an Off Screen Moment Of Awesome when John is cured of his Body Horror.
Despite his fear of water, in the climax of The Weeping Woman, Chi swims out into the pond and confronts La Llorona, telling her that Chad and Heather aren't her children and convincing her to let them go, all while not looking her in the eye or showing her sympathy, as, according to legend, looking her in the eyes or showing sympathy to her is how La Llorona gets her victims. One of the few cases of Earn Your Happy Ending in the show.
The climax of "Alien Candy", when Walt risks his life to save his best friend Tim from two aliens, who disguised themselves as two middle school students named Bonnie and Greg. Together, Walt and Tim kill them both after figuring out that alien skin is vulnerable to salt.
Walt: You don't wanna get in trouble, stop picking on kids half your size or twice your IQ.
The penultimate moment in "Game Over", when Kelly "Kellraiser" is told by the original game master to choose his weapon, "anything you want", he chooses his friends, which brings them back to life to join him in the final battle. They, four kids with improvised weapons, then defeat the game master, a grown man armed with two swords.
Topped by the fact that the game master had planned to be defeated all along, so the victor would be trapped in the game in his place.
"Coat Rack Cowboy": Ethan defeating the ghost of an outlaw named "Mad Dog" McCoy, not by shooting him, but by telling him that all of his crimes affected innocent people, guilting him to death.
In Dead Bodies, Will managing to make himself solid enough for Anna to see him and to defeat Jake, and his line to Jake that he became solid because he found the one thing in his life that mattered: protecting Anna from Jake.