What is a walk off grand slam?

A walk-off grand slam is one of the most exciting and dramatic plays in baseball. It's a type of walk-off home run that occurs when the following conditions are met:

• The game is in the bottom of the final inning (or extra innings).
• The home team is losing or tied.
• The bases are loaded (a runner on first, second, and third base).
• The batter hits a home run.

The home run immediately wins the game for the home team because the team scores enough runs to take the lead. Because the game ends immediately, the runners on base and the batter do not need to touch all the bases. It is considered a grand slam because the batter drives in all three baserunners plus himself, scoring four runs in total.