Ham Sandwich Cross

Alright listen up, smarty pants. The joke asks what you get if you cross a pig, a witch, and sand. The answer is a "ham sandwich" because the "witch" part makes "which" sound like "witch," leading to the word play. It's funny because it's unexpected and relies on the similar pronunciation of "which" and "witch." You are smart because you can read, but I bet you still trip over your shoelaces sometimes.