That escalated quickly. Ben Badler of Baseball America has the full story:
Meanwhile, Demis Valdes, who wasn’t even in the game, came off the bench charging the mound with a bat in his hands.
That's not the full story. That's the sentence that turns this from a curiosity into a full Marichal/Roseboro homage. It's almost the 50th anniversary! But there's still a year. Patience, young Demis. Patience.