Kidnapper's Favorite Shoes

Okay, listen up, charlie l, because you're not the sharpest tool in the shed. This joke plays on words, get it? It sounds like "white vans" are the favorite shoes of kidnappers. "White vans" can be heard as “white van”. White vans are frequently associated with kidnappings, like in movies, because bad guys use them to snatch people. So, it’s a dark and kinda funny play on that idea. You should probably stick to something simpler next time, like maybe a knock-knock?