McDonald's recently-released adult Happy Meal was designed to engender feelings of "nostalgia" among its older customers.

Instead, it's kicked off a bidding war.

The Cactus Plant Flea Market Box has already sold out at many McDonald's locations across the country, meaning that the only way for collectors to get their hands on the toys is through the secondary market.

Opportunistic resellers are taking advantage of McDonald's limited-time collaboration with streetwear company Cactus Plant Flea Market to try to make a quick buck.

Toys from the Big Mac combo meal are popping up on resale sites and fetching thousands of dollars.

One seller on eBay listed a trio of unopened toys — the four options are McDonald's mainstays Grimace, the Hamburglar and Birdie, as well as the apparel brand's mascot Cactus Buddy — for a whopping $300,000.95. "WILL SELL FAST!!" the seller added on their six-figure listing.

Another seller is asking for $25,000 for an unopened Happy Meal toy, and asks that the winning bidder also cover the $6.10 in shipping fees.

Both listings have yet to receive any bids.

But that's not to say that McDonald's fans haven't been willing to cough up the dough for the collectible toys.

One eBay listing that included 150 sealed toys was sold for $2,400 on Oct. 6, fetching an average of $16 per toy.

In New York City, the Cactus Plant Flea Market Box retailed for $12.95.

More than a dozen other 150-count cases have also sold for as much as $1,900, according to eBay's sales history.

For fans who missed their chance to get the collectible, McDonald's has already moved on to its next limited-edition release.

The fast food giant has brought back its collectible Halloween Happy Meal pails for the first time since 2016.

But move fast if you want to get your hands on one. They're already appearing on eBay, too.

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