Discarding the card triggers Sheriff, who deals damage to an opposing character, which in turn re-readies our Beast
In the future, I think this step could be improved by adding more specific and actionable advice about what makes good cards, like the guidance from this page
Speaking of modifications, lets talk about the other cards that just didnt make the cut for my sample list
Each creature fuels half of the engine
Brawl Not Legal Vintage Legal Timeless Not Legal Commander Legal Pauper Not Legal Oathbreaker Legal Penny Not Legal Toolbox Notes and Rules Information for Twenty-Toed Toad: If multiple effects modify your hand size, apply them in timestamp order
Its basically a one-mana Cryptic Command, and that comparison should show you why this is one of the best Modern sideboard cards