The goat emoji on its own almost never refers to the animal in teen messaging. It is shorthand for 'GOAT' — 'Greatest of All Time' — a sporting honorific that has spread to music, gaming and everyday praise. Sending a goat emoji under a friend's exam result, performance video, or basketball clip means 'you are the best'. It is purely positive. The capital letters GOAT come from boxing fans of Muhammad Ali, popularised in hip-hop by LL Cool J in 2000. Now universally understood by anyone under 30.