paul , 
Users and friends, filtering hashtag 診断メーカー works to keep the current wave of spam out of your timeline, mentions, etc, as this example shows.
Over 4.4K in the last 24-hours. I know many admins have been combating it all night to keep it out of your timeline.
Might not be a bad idea to set the filter up while #MastoAdmin's combat the problems.
If you're not curious, hide completely instead of just a warning as shown in the red circle..
timeline showing spam behind a hidden
timeline with a hidden post exposed