This morning I found in the phone an SMS reminder from the Google Calendar with the following content:
Reminder: Official Meeting; Mutual Benefits. Tue 15 Apr 6:30 am - 7:30 am
I subscribed to several calendars, but the notification indicated my personal one. Of course, I do not remember creating any such meeting.
Going into the Google calendar, I really found an invitation to a meeting:

In detail for the meeting were found 99 more invitees.

In general, there was no meeting anywhere, and the description is quite standard for spam. But the method, I confess, is new to me. I wonder how long such “meetings” began to appear in Google’s calendars?