Black Cat ^^ is a user on mastodon.social. You can follow them or interact with them if you have an account anywhere in the fediverse.
If you don't, you can sign up here.
#mastodon pro tip: if you're fed up with all the "RTs" in the timeline, you can hide them with a simple RegEx filter:
Just enter "RT @|RT:" in the "Advanced" line of the column settings
