Derek Jeter killed The Great Sea Race:

The Great Sea race, as it was called, began in 2012 with the opening of the Marlins’ new ballpark and featured four mascots: Bob the Shark, Julio the Octopus, Angel the Stone Crab and Spike the Sea Dragon. In the middle of the sixth inning, the four creatures emerged from a gate in center field before racing down the warning track to left-field corner and then turning for the finish line at third base.

Via The Big Lead, where Andy Nesbitt notes:

Now, did I know this race thing happened at Marlins games? No, no I didn’t. Will I miss it? No, I just told you I didn’t know it even was a thing. And while the sober me can live without a mascot race at a game, the 6-7-beers-deep me can see the fun of suddenly having something to cheer about at a Marlins game.

This is the first I heard of it as well. I did know the Marlins have real cheerleaders (as opposed to the young people in half baseball uniforms that throw T-shirts at people). I’d have kept the race and lost the cheerers.