If your Google Calendar seems like it's been hacked, here’s what to do - Quartz

A bizarre phenomenon bubbling up around the internet seems to have come to a head in the last few days. If you use Google as your calendar, you may have noticed a series of events on it that you don't remember being invited to, and probably have no interest in attending. ....
https://qz.com/1696839/how-to-stop-spam-events-on-your-google-calendar/