Martian swamp gas? Donald Trump? Oh wait, those are the same thing.
Beats me. At least it was easy to figure out!
Just for the sake of online security/paranoia, consider changing your Google password to something that is complex, and is not used on any other website. By "complex", I mean, at least 16 characters, with no words or names in any language, and no "clever" numeric substitutions like g00dpassw0rd. Something pseudo-random, like S#6y2WS2*k8xB4tQ is recommended. Never use the same password on more than one website that requires a sign-in. Consider using two-factor authentication.