Don’t say we didn’t warn you: “Tax the rich” always moves past “the rich” real fast.

It’s happening with Gov. Kathy Hochul and Mayor Zohran Mamdani’s new pied-à-terre tax before they’ve even figured out how to make it work (if they even can).

They announced it as a surtax on 13,000 uber-wealthy nonresident NYC owners of second homes worth $5 million or more.

Weeks later, Hochul’s office on Thursday suddenly “explained” that this actually means it could hit condos and co-ops with assessed values starting at just $1 million — far below what lots of units close for when sold.

The dynamic duo is only certain the scheme will bring in $500 million a year for the city; indeed, everything else about how the tax is to work seems reverse-engineered from that figure.

Now Hochul says it’ll hit only 10,000 such homes, though it’s hard to see how she can know that.

Also: The cutoff will be based not on market value, but on the properties’ current assessed values — numbers that nobody thinks have much to do with any reality.

Though the plan is also for a total restructuring of the city assessment system, which is so politically fraught that no one’s dared to do it for decades.

The gov and mayor plainly thought up the headline for this tax, and are still struggling to fill everything else about it.

Yet it seems to be headed to a citywide assessment of all one- to three-family homes, co-ops, and condos at their full market value, which would mean hefty tax hikes for a lot of modest earners entirely separate from the pied-à-terre.

Heck, at a $1 million cutoff, the surtax seems primed to hit plenty of one-bedrooms and even studios in the pricier parts of town — not exactly the Russian oligarchs and so it supposedly targets.

This is the perfect example of how “taxing the rich” never stops there.

How many middle-class homeowners across the boroughs will suddenly find their longtime family abodes suddenly being taxed as multimillion-dollar dachas?

Way to make even more middle- and working-class New Yorkers abandon the city. 

And this, from a pair who insist they’re championing “affordability.”

Mamdani’s seizing on New Yorkers dreams as a chance to play Freddy Krueger in a new “Nightmare on Elm Street.”

Can you feel “the warm embrace of collectivism” now?