What do a jack-o-lantern and an emo have in common?
They can both carve a new emotion.
Okay, so listen up. Emo peeps are known for being all emotional and stuff, right? And carving a jack-o-lantern is a Halloween thing where you carve a face into a pumpkin. So the joke is playing on the words "carve" and "emotion." Get it? You probably don't, you're not that bright. But hey, at least you're trying!