The former New Jersey governor addressed Mr Trump directly.
"Donald, I know you're watching. You can't help yourself" he said, pointing down the camera.
"You're ducking these things...You keep doing that, no one up here is going to call you Donald Trump anymore, we're going to call you Donald Duck".
The former president was not far from the minds of the Republican candidates with both Mr Christie and Mr DeSantis going after Mr Trump in his absence.