You need to get rid of the calendar these events are in. It appears this is the latest way to spread spam. The events are either in a subscribed calendar, or an email account with calendars turned on. It may also be a profile.
Start out by tapping on Calendar in the bottom center of the screen there. Do you see a calendar listed that you are not familiar with, and it should have a color matching that of the events you are seeing. If so, see if there is an (i) at the end of the line. Tap on it and see if you see a Delete calendar listed. If so, delete it. If not, the next step would be to check Passwords & Accounts. See if there is a strange email account listed there. If so, see if you can delete it, or at least turn off calendar. If that is not present, check Settings>General>Profiles and see if there is a strange profile present there.