The appearance, 30 minutes of starstruck screaming, dancing, and picture taking, was just the right amount of Gritty magic at Schwemlein's wedding for her now-husband Carl, also a Philadelphia sports fan.
"I didn't want it to take anything away from Heather," Grossmuller said. "I just wanted it to be something that Heather would remember that the two of us do together as daddy-daughter."
It was Gritty's high-flying entrance on a wrecking ball at the Flyers' first regular-season home game in October that ultimately won Schwemlein over after the team introduced the giant, orange googly eyed mascot to mixed reactions in late September.
And just like countless others, she fell in love with the fiery mascot, but she did not expect to get her own personal Gritty party on the biggest day of her life.
"We joked about it, but I never thought that would become a reality, ever," she said.
Initially, Grossmuller had requested through his season-ticket representative to have Gritty stop by their seats wearing a wedding veil, but because of the mascot's busy in-game schedule, the more feasible option was to get an appearance package that also included game tickets.
Grossmuller kept the whole thing a secret, not even telling his wife Linda. He got the wedding planner's contact information by asking Schwemlein if she could send him the itinerary for the wedding day, and begged the planner not to spoil the surprise. The version of the plan Schwemlein never saw only said a "high-profile guest will be coming."
And when Gritty blew through the doors early in the reception, the 225 guests in attendance at the ballroom in Northern Liberties neighborhood of Philadelphia went wild.
"He comes down and immediately starts dancing with me," Heather said. "He hugs the groom, the groom was yelling and screaming and we were just dancing with him. There were a couple of ladies that had red dresses and blonde hair and that was like his favorite type of woman. He was doing the heartbeat thing for those ladies. Oh my gosh, he was so hilarious."
The moment spread online as excited guests posted pictures and videos to social media of Gritty working the room.