Na ge is a common Mandarin filler phrase made from the demonstrative na and the measure word ge, roughly equivalent to that one. In everyday speech it fills pauses while a speaker thinks, similar to um in English, which is why a short isolated recording works so well online. Editors lift the moment out of conversation and reuse it as a standalone reaction on short form video and soundboards, where its brevity makes it easy to loop, layer over faces, and time precisely to a moment of hesitation or confusion for comic effect across different contexts.