Hunger of Hadar has this audio effect:
You open a gateway to the dark between the stars, a region infested with unknown horrors. A 20-foot-radius sphere of blackness and bitter cold appears, centered on a point with range and lasting for the duration. This void is filled with a cacophony of soft whispers and slurping noises that can be heard up to 30 feet away.
What mechanical game effect should these sounds have? I could see a DM ruling they might give advantage on some Intimidation check, or prevent hearing the movement of an unseen creature. But RAW, is that pure fluff text with no practical impact, or is it indeed intended that the DM somehow takes the effect into account, and if so, how?
Related: I asked a separate question about radius of the sounds (30′ from the center point, or 30′ from the sphere).