John Mika is a retired autoworker, substitute teacher and a self-described casual Buffalo Bills fan. Since 2011, he has been the director of The Teachers Desk, a Buffalo, New York-based nonprofit that collects donated school supplies and distributes them to students and teachers in need.

Mika's organization has passed out an average of 3,000 backpacks per year, each made possible by a $10 donation and filled with supplies valued at $100. Mika also created a warehouse "store" where teachers can gather $1,000 worth of free supplies. In total, the charity assists 250 schools and 150,000 students in the region.

On May 15, Mika received a call for his charity to fulfill a final wish of a Bills superfan, "Pancho Billa," who had died a day earlier after battling cancer. The fan, Ezra Castro, declined flowers for his funeral and instead asked for donations of backpacks with school supplies. Mika agreed to help.

Every Panchospack has this tag affixed to it, letting kids know why they are receiving a backpack filled with supplies. Thank you @biondoart #billsmafia & #allsafetechnologies pic.twitter.com/SdRbhe8H2N — The Teacher's Desk (@TeachersDeskBuf) June 10, 2019

"I'm thinking it's going to be just a little bit [of donations in Castro's memory]," Mika said this week. "Just a few hundred dollars -- a hundred backpacks, or whatever."

Later that day, word about Castro's wish and links to donate to The Teachers Desk flooded social media channels frequented by Bills fans. While Mika was in a meeting, notifications from the donations began to rattle his phone.

"It's pinging dozens and dozens and dozens a time a minute," he said. "I'm like, 'What is going on here?'"

In total, the Teachers Desk has raised more than $100,000 since the start of the drive -- enough to assemble more than 10,000 backpacks with supplies valued at more than $1 million.

Ready, set, pack... 6...#PanchosPack stations are ready for a miracle on Monday. Thank you volunteers for all you do. We are absolutely blessed at the Desk.#billsmafia #theteachersdesk pic.twitter.com/c3qU3KhqNH — The Teacher's Desk (@TeachersDeskBuf) June 8, 2019

Call it the Bills Mafia effect. The request to Mika had come from Del Reid, the co-founder of the nonprofit Buffalo FAMbase and a key voice in past fundraising efforts among Bills fans. The fan base, which has adopted the moniker "Bills Mafia" over the past decade, donated about $450,000 to Andy Dalton's foundation after the Cincinnati Bengals quarterback's miracle Week 17 touchdown pass put the Bills in the playoffs in 2017.

Bills Mafia had also raised more than $150,000 for former linebacker Darryl Talley in 2014 when he revealed his post-career hardships. It donated to a pediatric cancer foundation in Chicago last year after Bills fans were called "the laughingstock of the NFL" by a Chicago sports network. This year Bills fans, convinced Titans fans cheated on a Twitter poll tournament crowning the NFL's best fan base, responded by giving about $16,000 to a Nashville-based children's charity.

Bills fans had similarly rallied around Castro, even before his death. The 39-year-old mortician from Dallas, known for his sombrero and mask adorned in Bills colors, was diagnosed with spinal cancer in 2017. Among the efforts to support Castro's family during his treatment was a GoFundMe page that raised almost $60,000.

After Castro campaigned on social media to announce a Bills selection on stage at the 2018 NFL draft in Dallas, the team obliged by having former stars Andre Reed and Fred Jackson yield the microphone to Castro, in full costume, who shared the pick of third-round defensive tackle Harrison Phillips.

"He was everything that a Bills fan is, right?" Reid said. "He was over the top in the way he presented himself. He was bold. ... He was not shy. He had a big heart. I really felt like he was a personification of what it means to be a Bills fan."

That moment led to more opportunities for Castro to interface with the team, including giving a pregame speech to players before a win last November at MetLife Stadium against the New York Jets. After scoring a touchdown in that game, wide receiver Zay Jones held up a white towel to television cameras with "Pancho Power" written on it.

After entering hospice care in April, Castro was offered the chance by general manager Brandon Beane to relay the Bills' first-round selection of defensive tackle Ed Oliver by phone to the team's draft table in Nashville. Oliver later visited Castro in the hospital.

The Bills plan to honor Castro at their home opener this September. In the meantime, Phillips and four other players -- linebacker Lorenzo Alexander, long-snapper Reid Ferguson, offensive tackle Dion Dawkins and kicker Stephen Hauschka -- have been among those working to carry out to Castro's mission of equipping children for school.

On Monday, those players were among 300 volunteers helping to fill backpacks at New Era Field for The Teachers Desk. Mika said there were at least 700 or 800 people willing to volunteer before a limit needed to be imposed. In three hours, the packers assembled 5,000 backpacks. Of those, 3,000 were shipped to Dallas and Castro's hometown of El Paso, Texas.

"They called him a Bills superfan, but in my book, he's a superfan of education," Mika said. "There's all kinds of folks wanting to be involved now. You combine integrity -- which is what we live here for -- education, and now you combine it with people who are crazy for sports. To me, it's incredible. It's a miracle."