Stephen Colbert asked tonight’s Late Show guest, Sen. Bernie Sanders what he would like to ask upcoming show guest Hillary Clinton, given the “pony” gag Clinton made about Sanders in her new book on the 2016 election. “What Happened.”

In “What Happened,” Clinton takes a swipe at Sanders, using a supporter’s Facebook post that portrayed Bernie and his supporters as having deliberately misrepresented her:

BERNIE: I think America should get a pony.
HILLARY: How will you pay for the pony? Where will the pony come from? How will you get Congress to agree to the pony?
BERNIE: Hillary thinks America doesn’t deserve a pony.
BERNIE SUPPORTERS:Hillary hates ponies!

“We have got to think ‘Going Forward’,” Sanders told Colbert in response. “I would like her to join us in the fight for a Medicare-for-all single payer system, in taking on the fossil fuel industry so we transform our energy system away from fossil fuel and move toward sustainable energy.

“We need her help to go forward. Let’s not keep arguing about 2016,” Sanders suggested.

“Let’s get together, take on Trump’s desire to divide us up. Let’s go forward with a progressive agenda.

“Ask her if she will do that,” Sanders said as Colbert’s crowd expressed wild enthusiasm for the idea.