— A professional basketball player who made headlines by calling the Apollo moon landings into question has taken his "moon boot" out of his mouth and put it up for auction.

Golden State Warriors point guard Stephen Curry is offering his custom lunar landing-inspired sneakers to raise funds for science, technology, engineering and mathematics (STEM) educational program in the Oakland, California area. The Under Armour "Moon Landing" Curry 6 basketball shoes are now open for bids on eBay through a partnership between the auction site, DonorsChoose.org and the Stephen and Ayesha Curry Family Foundation.

The sneakers, which celebrate "the great American achievement of landing on the moon" 50 years ago, hit the auction block on Sunday (Jan. 6) with an opening bid of 99 cents and quickly shot up to more than $4,000 with the first 50 bids. The sale extends for a week, closing Sunday, Jan. 13 at 7 p.m. EST (0000 GMT Jan. 14).

Update (Jan. 14): The auction ended on Sunday (Jan. 13) with 113 bids from 20 bidders, raising $58,100 for STEM education programs in the Oakland area.

"I've got my moon-inspired Curry 6's, custom made, that are going to auction. The auction is live now on eBay," said Curry in a video posted to Twitter on Sunday. "All of the proceeds will be going to support STEM education programs throughout the Bay Area through DonorsChoose.org."

"Hope you guys participate, it is all going to great cause," he said.

Curry drew international attention in December for doubting astronauts had walked on the moon.

"We ever been to the moon?" Curry asked on the "Winging It" podcast. His query followed lighthearted banter about how we know — or don't know — what sounds the dinosaurs made, as depicted in the movies.

The podcast's co-hosts and fellow NBA basketball players Vince Carter and Kent Bazemore both replied no.

"They're going to come get us, but I don't think so either," said Curry. "Sorry, I don't want to start conspiracies."

After the exchange went viral on social media, NASA reached out to Curry to offer him a tour of its moon rock lab at the Johnson Space Center in Houston. Curry quickly accepted the agency's invitation and insisted in interviews that he believed we landed on the moon "one thousand percent."

"Obviously, I was joking when I was talking on the podcast," Curry told ESPN.

Curry has yet to visit NASA, but he wore the "Moon Landing" shoes on Thursday (Jan. 3) during the Warriors' game against the Houston Rockets at Oracle Arena in Oakland. The sneakers, which feature a cratered lunar surface design and borrow colors from the moon boots worn by the Apollo astronauts, are one of only two pair that were hand painted by artist Dan Gamache of Mache Customs.

Curry autographed the pair that is up for auction. The shoes come with a letter of authenticity from his company, SC30, Inc.

Bidders must be pre-approved before participating given the potential high value of the "Moon Landing" shoes. In 2017, Curry offered a different pair of sneakers on eBay, raising more than $45,000 for the Oakland Fire Relief Fund.

Twelve NASA astronauts walked on the moon during six Apollo missions. Curry's auction is one of the first events in 2019 to coincide with the 50th anniversary year of the Apollo 11 first moon landing in July 1969.

For more details or to bid, see the Stephen Curry's "Moon Landing" Under Armour Curry 6 Shoes on eBay.