Back in 2017 when Harvey Beaks wasn't cancelled (I miss those days), I drew 4 page long comics of the show.
This is one of them.

This comic is based on the episode "Rockbark Rocks". More specifically, this one tumblr post based on the episode.
Someone asked Greenblatt where the twins were during the episode and this was his response (click here) I don't think he was being serious but I kind of associated that with being sick and got the idea to draw this.

Harvey Beaks © C. H. Greenblatt and Nickelodeon