What has 12 hooves, eight tails, six claws, a horn, night vision and cold blood, and is about to spark a walk-off #CurlyW? The Barnyard Pump, that's what.

No one is exactly sure how The Barnyard Pump came to be, but legend has it that the Nationals' entertainment staff accidentally invented the stampede-like activation while trying to conjure up a game-winning hit during the 2016 season. As the entertainment staff looked to inspire a fantastic finish, mascot after mascot poured out of the tunnel just up the left-field line from the visitors' dugout at Nationals Park to throw T-shirts, wave signs and generally get the crowd as hyped as possible. The Chick-fil-A cow. The GEICO Gecko. A chicken. A raccoon. A giraffe. A snake. Even the Easter Bunny took a break from haunting Teddy's nightmares to partake in the festivities.

Washington Nationals Entertainment Director Tom Davis opined that left field looked like Old MacDonald's Farm and suddenly the happy accident turned into an idea with legs, paws and talons.

Over the rest of that season and the two that followed, The Barnyard Pump evolved from a happy accident to a strategic measure deployed with cautious excitement. Witnesses state that it was deployed in the middle of the ninth inning of the 2018 All-Star Game at Nats Park, just before Reds slugger Scooter Gennett deposited a game-tying home run into the bullpen to send the Midsummer Classic to extras.

It's also said that The Barnyard Pump was seen at Nats Park immediately before Mark Reynolds hit a leadoff double in the bottom of the ninth on Sept. 3, 2018. He was lifted for pinch-runner Michael A. Taylor, who soon thereafter came home to score the winning run.

The 2019 season marked the beginning of The Barnyard Pump as an official in-game entertainment trigger to be deployed any time the score is tied heading into the bottom half of an inning from the ninth onward. Through five home games in 2019, Davis has activated The Barnyard Pump twice, and it's already inspired two incredible finishes to, ahem, barnburners at Nats Park.

On Sunday, March 31, the Nats and Mets were tied heading into the bottom of the ninth. Davis deployed his whimsical zoo out into left field, and moments later Trea Turner blessed the crowd with his second career walk-off home run.

Then, on April 3, the Nats and Phils had gone back and forth in a seesaw affair until The Barnyard Pump reared its various maned heads prior to the last of the ninth. Nats prospect Jake Noll thanked the animals for their hard work by working a walk-off walk for the first RBI of his MLB career.

Coincidence? We think not.

But Davis and Co. aren't done there. In advance of the 2019 season, the Washington Nationals Entertainment department made a few additional tweaks to ensure the activation would have maximum impact and some of those additions will be, uh, charging into Nats Park in the upcoming months.

First, since a stampede isn't really a stampede unless there's a rhino leading the charge, the Nats worked with Medliminal, a medical cost containment company and a new corporate partner of the Nats for 2019, to add a captain of sorts, effectively rounding out The Barnyard Pump's roster.

Finally, Davis and his team are working with the newly bolstered #CurlyW Productions staff on an intro video worthy of hyping up The Best Hype Team in Baseball.

So, if the score is tied late in a game at Nats Park, be sure to check the tunnel down the third-base line at the inning break because a whole gaggle of animals are gonna storm out onto the field, two-by-two to make sure the crowd and the team are ready to run through a brick wall for a #CurlyW!