Chris Carter didn’t waste a moment transforming Citi Field into “Animal” Planet last night.
The Mets’ new arrival — nicknamed “The Animal” by manager Jerry Manuel in spring raining because of his intense workout habits — became a fast hero by stroking a go-ahead, RBI double in his team’s wild 8-6 victory over the Nationals.
Almost dead and staring at a third straight defeat, the Mets scored six runs in the eighth nning for their biggest comeback win of the season.
“It’s how I dreamed it up,” said Carter, who arrived from Triple- A Buffalo to replace the ousted Frank Catalanotto off the bench.
Called upon to face Tyler Clippard after the Mets had already scored four runs to make it -6, Carter smashed a shot into the right-field corner that scored Alex Cora. Later in the nning, Jason Bay walked with the bases loaded to provide insurance.
The Mets (18-15) totaled a season-high 16 hits and could forget the fact they nearly let the Nationals off the hook by leaving 10 runners on base.
“We kept putting people out there,” Manuel said. “It looked like every inning we had a shot. But those guys are tremendous fighters. There is great character on this team.”
The Mets were 0-12 when trailing after six innings and appeared ready to extend that futility when they came to bat in the eighth against reliever Brian Bruney trailing 6-2.
But Bay singled leading off and David Wright doubled him to third before Ike Davis
hit a grounder that shortstop Ian Desmond threw away. Bay would have scored anyway, but it gave the Mets an extra out and baserunner.
After Clippard entered and struck out Jeff Francoeur, Rod Barajas hit a two-run double off the left-field fence. Cora then bunted for a hit and Angel Pagan’s RBI single tied the game. Then Carter untied it.
“Once [Cora] put that bunt down, the confidence was extremely high, like ‘We’re going to win this,’ ” Carter said.
Bay and Wright each finished 3-for-4 with an RBI and Ike Davis punctuated the victory by falling over the railing by the first-base dugout to snare Desmond’s popup for the final out. It was the third time this season Davis has made such a catch.
Jonathan Niese lasted only 41/3 innings and surrendered six earned runs in his worst start of the season, but Manuel can thank Manny Acosta, HisanoriTakahashi, Raul Valdes (1-0) and Francisco Rodriguez for saving the day by combining for 42/3 scoreless innings.
The Nationals appeared to seize control in the fifth, when they sent nine batters to the plate and scored three runs. Ivan Rodriguez’s two-run single chased Niese before esmond delivered an RBI single against Acosta.
Adam Dunn’s three-run homer in the first inning got the Nationals started. Cristian Guzman walked and Ryan Zimmerman singled before Dunn connected on a 3-0 pitch and lofted a fly ball that landed in the front row of the right-field seats.
Francoeur’s RBI single against Scott Olsen in the second pulled the Mets within 3-1. Wright’s leadoff double in the sixth led to the Mets scoring their second run —on a Francoeur sacrifice fly.
Bay said the Mets were due for their eighth-inning outburst. “We’ve had chances the last few games and were just not capitalizing on them,” he said. “[Tonight] was just one of hose things where everything went right.”
mpuma@nypost.com