Baghdad-based spokesman Colonel Steve Warren recounted the exploits of the M-1 Abrams tank in Heet in response to a question about whether the Iraqi military is taking too long to expel IS jihadists and lacks the will to fight.
On Monday, Iraqi security forces (ISF) raised the Iraqi flag over government buildings in Heet, in Anbar province.
"This M-1 tank has been driving all around Heet, crazy, and blasting IEDs (roadside bombs), punching holes in enemy defenses and maneuvering between multiple engagements," Warren said.
"This tank has become a little bit of a folk hero here in Iraq. They've nicknamed this tank 'The Beast.' So now all of a sudden, The Beast has become a thing here."
Warren later re-tweeted a video of the tank -- provided by the US -- blowing up a car purportedly carrying explosives. Three tanks had initially been deployed to Heet but two were out of the fight for mechanical reasons.
The US military is keen to highlight examples of Iraqi security forces making progress against the IS group, which seized vast swathes of Iraq and Syria in 2014, including the key Iraqi cities Ramadi and Mosul.
Despite some major setbacks, including the recapture of Ramadi, the IS group still controls large areas of the two countries and critics have accused the US-backed Iraqi military of lacking the skills and temperament to fight back.
Warren said The Beast illustrates a fresh resolve for Iraqis to fight the IS group and he praised the actions of some units, especially the Peshmerga of Iraq's autonomous Kurdish region.
"We are seeing these examples over and over of small units whose confidence, whose competence, whose morale is growing and strengthening and expanding," he said.
"That tends to have... a ripple effect across units."
"We estimate that 75 percent of the city (Heet) is now clear and that ISF will push (the IS group) completely out of the city in the coming days," he added.