MLB. Has a pitcher ever thrown a tantrum when asked to give up the ball?

Denkinger clearly blew the call. But it would have been the first out of the inning, and the rest of what happened in the 9th was entirely the Cards fault. In fact, they retired Orta (who reached on the bad call) at third eventually anyway; the only out they managed to make.

You can argue that the bad call rattled them, but they were professional baseball players playing in the World Series and should not have let themselves be rattled. The loss is entirely on them.

Minor nit, but that happened on Saturday, June 18, 1977. I missed seeing it live by a day as I attended my first game at Fenway Park the following day.

There was a Blue Jays pitcher, circa 1990, who after being removed, threw the ball down the left field line. Want to say it was David Wells, but I’m not sure.

Found that one - you’re right:

In an August 1991 home game against the Boston Red Sox, Jays manager Cito Gaston went to the mound to get Wells after the pitcher had given up nine hits and five runs. When he put out his hand to get the ball, as is the custom, Wells refused to give it up. The two had words and Boomer threw a mini tantrum, throwing the ball down the left field line, much to the displeasure of his manager.

A story from 1934 also had a pitcher throwing the ball away when the manager came out to remove him:

On July 4, 1934, Brooklyn manager Casey Stengel went to the mound to remove his pitcher, Boom-Boom Beck, in a game at Philadelphia’s Baker Bowl. Beck, irate because he was being taken out of the game, fired the ball off the tin rightfield fence. Rightfielder Hack Wilson, who was badly hungover from a night of drinking, heard the sound of the ball hitting the wall and raced toward the fence. He retrieved the ball and and made a perfect throw to second to nail the phantom runner.

And one more, from 1980:

Luis Tiant, the Yankees veteran right-hander, lost his cool when Howser removed him from the game with a 4-0 lead over the Toronto Blue Jays in the eighth inning and tried upstaging his manager by throwing a mini tantrum which included flipping the ball instead of handing it to Howser and then tossing his glove into the stands as he walked toward the dugout.