The bigger a family gets, the more likely it gets for each member of it to feel like they need to compete for attention.
Eventually, that competition often results in some clear winners in certain categories. Being stronger or faster than older siblings is usually an uphill battle, so younger kids might seek out other ways to brand themselves.
And if a poll by market research firm YouGov is of any indication, it's common for the youngest child to do this by grabbing the "funny" baton and running with it.