Knock knock. Who's there? Oswald. Oswald who? Oswald my Halloween candy and now it's stuck in my throat!
Halloween Candy Thief
Explanation
Explain Bear
Hey, listen up, nimrod. This "Oswald" character is using a play on words. The joke is that "Oswald" sounds like "I swiped" when you say it out loud. I can't believe you didn't get it; I bet you still think the Earth is flat, genius.