She said if Harawira told his voters not to vote for the Maori Party, the Maori Party would tell their voters not to vote for the Mana Party. Na-na-na-na-na.
It was a blunt reminder Harawira might need the Maori Party more than they needed him despite the imbalance in the electorate seat deal.
The Maori Party is a cock-a-hoop at the moment on the back of a One News Colmar Brunton poll putting them at 4 per cent support, up from around 1 per cent.
It would normally be seen as a rogue result - but there had been a lot happening in Maori politics to give it some credence.
As well as the Mana-Maori deal, the Maori King had endorsed the Maori Party and its proposed Waikato Tainui candidate Rahui Papa over Labour's Nanaia Mahuta.
They also came under sustained attack from Labour leader Andrew Little, who repeated his view of the Maori Party as a mere tuktuk falling off the back of his "cab rank" in any post-election coalition talks.
He then announced the Maori Party were not a kaupapa Maori party because of their links with National.
Maori politics can be dynamic, but it does not take a Maori kaupapa expert like Little to judge who Maori voters are more likely to side with between a Maori and a Pakeha politician.
It is possible Little's declaration did more good than bad for the Maori Party.
With all of that going on, it seems likely there was some boost in support for the Maori Party.
It coincided with the decision by Labour's Maori MPs not to stand on the list. Those MPs may well be a tad nervous about that decision if subsequent polls show the Maori Party is indeed enjoying something of a political resurrection.
Fox's job is to make the poll boost last.
She was helped when Labour pulled its support for a measure to allow Ngati Paoa to buy back a little-used portion of Pt England Reserve for a housing development and a marae under its Treaty settlement.
That provided Fox with an example of the Maori Party's argument that Labour's Maori MPs had to toe the party line even where that went against Maori interests. The Maori Party did not.
The Resource Management Act reforms unexpectedly provided a further opportunity - courtesy of Act and NZ First.
The Maori Party gave the National Party its votes in return for changes including new iwi participation agreements and preventing ministers over-riding councils' decisions on GE crops.
Act and NZ First seized on the iwi participation agreements, building them up into the boogie man hiding under the bed. NZ First leader Winston Peters described it as "separatism" and the Government caving into "brownmail". Fox called that out as hyperbolic scaremongering.
She began her speech to Parliament with feigned horror: "Oh my goodness! Lock up your children cos here come the Maoris and we should all be very scared."
But she probably didn't mind at all. The more National is accused of "caving in" to the Maori Party and giving up too much to iwi, the happier the Maori Party is because it makes it look very powerful indeed to its voters, Maori voters.
One of Peters' regular sledges of Fox in Parliament is a supposed Maori proverb "when the hen starts crowing, wring its neck". It is a rather sexist way of saying she is getting too big for her boots.
Fox would prefer another fowl-related proverb: something about a fox in the henhouse.
