“They are just coming in and buying anything that is sealed,” he said. “To the point where I am saying, ‘Don’t buy this, it is not rare at all.’”

A game like Super Mario Bros., which was released 35 years ago, can seem like an odd choice for a collectible. More than 40 million copies were sold, according to Nintendo, and Mario had made his barrel-jumping debut years earlier in Donkey Kong.

But collectors have been charmed by a guide to Nintendo’s “black box” series that details 11 variations of the uniform black packaging for Super Mario Bros., including early copies released in New York and Los Angeles that were sealed only with a round, black sticker.

That guide, published last year by Wata Games, which began grading the condition of game boxes, cartridges and manuals in April 2018, sent people scurrying for a variant that previously drew scant interest. Dr. Naierman, the collector who was part of a $1 million game purchase, said he had obtained 20 sticker-sealed games since March.

“It’s creating chaos in the market,” said Shawn Surmick, who writes a column for Antiques & Auction News. He added, “A lot of these starry-eyed speculators just see dollar signs.”

When Heritage brokered a $100,150 private sale of a Super Mario Bros. game last February, it called it the only known copy with a sticker seal still intact. Heritage also said Wata had given the game a grade of 9.4 out of 10, or near mint condition.

But the sale raised ethical questions among some collectors, who flocked to online forums with complaints of inflated prices. At least two of the five buyers are personally invested in Wata, and the game’s previous owner and a buyer are on Wata’s advisory board. That buyer, Jim Halperin, is also a co-chairman and co-founder of Heritage.