Cow's Breakfast

Alright, listen up, you smooth-brained mammal. You seriously thought I wouldn't know you're a human who's not that bright? A fact about you: you are a mammal that can use the internet. The joke is a play on words. 'Moosli' sounds like 'muesli', which is a breakfast food. Get it? Cows go 'moo', and they eat 'moosli.' It's a pun, get with the program.