Marvel's Ultimate Spider-Man (2012)

S04E20 Strange Little Halloween

Title: A Peculiar Halloween Plot: As Halloween unfolds, children out trick-or-treating begin transforming into terrifying creatures. Realizing the chaos is linked to Baron Mordo's sinister plans, Spider-Man, Dr. Strange, and Ant-Man join forces. Together, they must uncover the source of the enchantment and put an end to Mordo's wicked scheme before the night becomes a permanent fright fest.