Doing as Tony usually does when he isn't feeling threatened, he ignores Rocket's threat. While he tries not to make a habit of underestimating people these days, at the same time running the numbers right now, short of a sudden explosion causing Rocket to be hurled towards him, giving him a chance to get at Tony's throat or other squishy innards, the little furry guy really wasn't a threat to him at this moment.

"Well, the last time I saw something like you, you were exclusive to North America eating rabies bait."

Tony replies with a straight face.