Fox News
Ted Cruz.
Fox News moderator Chris Wallace asked Cruz to discuss how his plan to defeat ISIS was different than other presidential candidates' plans.
The senator used his answer to sneak in a jab at Trump, even while he complained that the moderators were asking him unfair questions.
"Gosh, if you guys ask me one more mean question, I may have to leave the stage," Cruz quipped as the audience laughed.
This wasn't the first time that Cruz made a joke out of Trump's decision to boycott the debate over perceived unfair treatment by the network and one of the debate's moderators, Megyn Kelly.
Earlier in the evening, Cruz responded to a question about Trump's boycott by channeling the real-estate magnate himself during the debate.
"Let me say that I'm a maniac and everyone on this stage is stupid fat and ugly, and Ben, you're a terrible surgeon," Cruz said, referring to retired neurosurgeon Ben Carson.
"Now that we've got the Donald Trump portion out of the way, I want to thank everyone here for showing the men and women of Iowa the respect to show up and make the case to the people of this state why each of us would make the best commander in chief," he continued.
At least one presidential candidate promised that they wouldn't leave the debate in protest.
"Don't worry - I'm not leaving the stage no matter what you ask me," Sen. Marco Rubio (R-Florida) said.