A cat ran onto the field at Busch Stadium, and Yadier Molina hit a grand slam on the next pitch

It was a tense situation at Busch Stadium on Wednesday night. The Royals and Cardinals were playing a key Interleague series for both teams, but especially the Cardinals, who entered the game just two and a half games back of the Cubs in the competitive NL Central.
Royals reliever Peter Moylan was clinging precariously to a 5-4 lead in the bottom of the sixth. Two men were down, but the Cardinals had the bases loaded for Yadier Molina. Moylan delivered a pitch for a ball, and then, out of nowhere, a tiny cat stormed onto the field.
Its first stop was saying hello to center fielder Lorenzo Cain:

What a kind kitty!
Cardinals manager Mike Matheny was caught off guard by the team's new guest. "I didn't see anything until all of the noise," he said to MLB.com's Alaina Getzenberg. "I thought there was a streaker on the field to be honest, but I was happy it was a cat." 
A stadium employee did eventually have to track the feline down, but it wasn't ready to go:

It did not take well to its ballgame experience being cut short, scratching and biting at the poor guy as he ran off the field with it. Chances are, it's a descendent of the cat that wreaked similar havoc on a Kingdome employee in Seattle back in the day:

The levity was broken on the very next pitch, when Molina crushed a game-changing grand slam to put the Cardinals ahead:

The 8-5 lead held, and the Cardinals won. They leapfrogged the Brewers to jump into second place in the NL Central, a mere game and a half behind the Cubs. "I'm not a cat person, but I sure like that one," Matheny joked after the game.
It wasn't be the first time that the Cardinals have received inspiration from the animal kingdom, either, having benefited from the "Rally Squirrel" in the 2011 NLDS. Molina remembered. "It was the catcher that told me like, 'You haven't seen something like that before,'" he said. "I said 'Not with a cat, but a squirrel, yes.'"

Molina often goes by the nickname "Yadi," which he'll wear on his jersey during Players Weekend on Aug. 25-27. So, in that vein, just call the Cardinals' new feline friend "Yadi the Rally Cat."