WATCH: Triumph the Insult Comic Dog mocks Ted Cruz for letting Trump 'neuter' him

Triumph the Insult Comic Dog mocked Sen. Ted Cruz (R-TX) to his face at a campaign rally for CBS' "The Late Show."

Stephen Colbert sent Triumph, played by his former "Dana Carvey Show" colleague Robert Smigel, to Texas to cover rallies for both Cruz and Democratic challenger Beto O'Rourke.

“Ted, is it true that you’d defend the Constitution at all costs," Triumph said, "except for when Donald Trump calls it ugly on Twitter?”

“I love the Constitution," Cruz said, "and Twitter is Twitter."

A security guard tried to keep a distance between the Texas Republican and the puppet dog, who continued teasing Cruz.

“Let’s be civil here, OK, because this man — nobody should be yelling at this man in a public place,” Triumph said. “I mean, doesn’t this man have the right to sit down in a restaurant and enjoy a meal that five waiters have spit in?”

Cruz tried to retort with a joke about Democrats taking Triumph to a veterinarian to be fixed, but the puppet had the last laugh.

“I support spaying and neutering, just like Trump did to you!”

Triumph then goaded Cruz supporters to chant that he's a "lion of the Senate," which the puppet then turned into a chant of "lyin' Ted."