This is a very effective insult used in online gaming. Not only are you asserting dominance, but you are also telling them that they are black and a slave. This is a term coined by the great fortnite player named "adjoinFRAGS".
Guy1: "Adjoin, you're trash, kid"
adjoinFRAGS: "Shut the fuck up kid I own your family"
Guy1: *shuts up*
A rather unknown internet meme. One user will go on to a chat program -most commonly omegle- and tell the receiver "I own a horse." .The other person then disconnects.