I answered, there was a loud buzzing-ish noise, and then the line went dead.
I keep receiving this call with an automated voice stating my car's warranty is about to expire. I know it isn't legit because both my cars are over 20 years old and have been in my family almost as long. It asks if you want to speak to a representative about the warranty but when you say yes it hangs up.
Claims to be Social security administration.