Rav Meir Chodosh?
I can't seem to find it anywhere online when I searched his name.
I seem to remember it being Rav Gifter, but perhaps I'm mixing it up with another story, which I heard directly from Rav Gifter's rebbetzin:
At one point, Rav Gifter lived in the same building as the dorm, and he had to pass by the bochrim's rooms to get to his apartment. Once, as he walked through, he heard a bochur imitating his style of speech. The bochur caught sight of the rosh yeshiva and stopped abruptly, very embarrassed. Rav Gifter defused the entire situation with a single quip: "Gantz gut. Uber Ich ken ton besser!" ("Pretty good. But I can do it better!")