Those thieving mfs using the spare Netflix profile you generously let a friend use.
Netflix second cousins are born when a friend, sibling, or ex shares the password to your Netflix account with their own friends, causing chain immigration into your hard-earned account. They burrow in the profile you don't use and suck the blood out of every last episode of Riverdale or, if they're your actual cousins, Rick & Morty. Netflix second cousins are the reason respectable people get ads targeted to people who still watch Family Guy.
Grateful Netflix second cousins will sometimes refer to the account owner as Auntie/Uncle Netflix. They are $10 richer than him or her.
1: "Why are GI Joe and Adventure Time suggested on your Guest account?"
2: "No doubt something to do with my Netflix second cousins and the phrase 'I'm sure he wont mind.'"