ALBANY — It was 20,000 creatures beneath the sea!

The artist commissioned to paint Gov. Andrew Cuomo’s nutty, nautically-themed third-term poster tried to encourage the pol to “pare” the painting back and find other monsters for the much-mocked piece.

“Are there too many cephalopods in the house? Should we pare this down and try other monsters,” Brooklyn-based Rusty Zimmerman told The Post he asked Cuomo as the two completed the painting.

But that didn’t stop Cuomo from repeatedly trying to jam even more things onto an already-packed canvas.

New York’s most powerful pol at one point pushed to include include his favorite classic car — Franklin D. Roosevelt’s Packard — on the poster, but Zimmerman said they couldn’t find a way to make it fit.

Other late Cuomo adds made the cut, including an ant-sized recreation of the famous duel between Alexander Hamilton and Aaron Burr.

And the governor kept trying to add even more octopuses and squids, eventually jamming three more into the painting.

“There is a certain amount of beauty, a wonderful breadth of beauty that comes with walking through the world with the willingness to say ‘yes’,” Zimmerman said.

The pair spent two months working on the poster after Cuomo sent him an initial sketch in November that depicted his administration as a ship sailing through waves adversary — all as a metaphor for his third term, done in the style of a nineteenth century political cartoon.

“If your adversity decides to hit you head on sometimes you have to just sail steadfastly onward despite what seems overwhelming,” Zimmerman added. “That’s what the ship was meant to symbolize.”

Drawing, Cuomo told Zimmerman, is not his “strong suit,” a nearly unthinkable admission from a man famed for his domineering personality.

The 40-year-old painter went on to describe Cuomo as humble and as a dream of a client, providing the public with a rare glimpse of the softer side of a man known for his Machiavellian view of politics and years-long grudge matches.

“He’s a very personable, affable guy and open to constructive feedback,” Zimmerman said.

The poster that ignited a storm of mockery on social media is the third the two men have worked on together, but Zimmerman stood firmly by his co-creation.

“It was a great privilege and I was glad to have been of service,” he added.