Leprechauns are stupid. No joke.
Are you a toaster?
Okay, so this joke is like, not even trying to be funny. It starts by saying leprechauns are dumb, which is kinda mean and not really a setup for anything. Then it just asks if you're a toaster. It's so random and pointless that it's almost funny, but mostly it's just... there. You probably think it is funny because you probably eat crayons.