Can I get in trouble if I lie to my former boss's partner?

Hypothetically, suppose I was fired unjustly and wanted to get back at them.

Hypothetically, if I wrote to my former boss's friend on facebook, using a fake Facebook profile made with a burner email and a VPN, and told them "Hey tell your significant other to stop hitting my boyfriend"

Hypothetically, is there a way that I can be traced, if I blocked the account and deleted my account before they read the message?

And is Slander something that I can get arrested for, or get sued? Thank you for your answers.