Businessman Sean Casten, facing Rep. Peter Roskam (R-IL) in an expensive suburban Chicago district, announced Tuesday that his campaign has raised $2.6 million in the past three months.

That’s not a typo. And it’s not even the highest total announced by a House Democratic challenger in the last few days.

A number of House Democratic challengers are posting truly eye-popping fundraising totals, numbers that have almost never been seen in previous election cycles and a sign that the progressive fury at President Trump and his party continues to express itself in huge campaign donations. That could help Democrats expand the House map in the race’s final month, allow national groups to make some calculated bets on late-breaking races and give the party more paths to the House majority. If this turns into a true tsunami, it could also help Democrats not just win the House but win big.

Marines veteran Amy McGrath raised $3.6 million for her race against Rep. Andy Barr (R-KY) — potentially more than she’ll even realistically be able to spend in the next month on advertising and field operations.

Venture capitalist Josh Harder wasn’t far behind, raising $3.5 million for his close race with Rep. Jeff Denham (R-CA).

Even some Democrats who haven’t been viewed as top-tier challengers (or as facing lightning-rod opponents who help them print money) have posted some huge totals. Rep. John Katko (R-NY) is a moderate Republican who’s been viewed as fairly likely to win reelection in his Democratic-leaning upstate New York district, but his Democratic opponent, educator Dana Balter, still raised $1.5 million in the last quarter.

For context, just seven House Democratic challengers who weren’t self-funders broke the $1 million mark in their third-quarter fundraising two years ago, according to Politico.

There are a few caveats. Candidates don’t have to report their fundraising totals from the end of September for almost two more weeks, and generally the worst-faring candidates try to bury their totals right before the deadline. And cash doesn’t necessarily translate to votes — Georgia House special election candidate Jon Ossoff fell just short in spite of raising nearly $30 million (!) for his race.

But Democrats’ millionaires’ club will keep growing, putting further pressure on big-spending GOP outside groups to cut loose incumbents they don’t think they can save. Five other Democratic challengers had raised over $1 million online through ActBlue from July through August, two thirds of the way through the fundraising quarter, and there were more than a dozen others who’d already topped $600,000 by Sept. 1. Since fundraising tends to pick up in September, many of those will top $1 million as well.

Republicans privately tell TPM that those numbers are alarming.