Authors CurseForge

Do not try adding/editing to mpq file, that will most definately get your account banned.

Since you know the file path, you can put a empty wav file to match it to get rid of the sound.

 WoWDir\Data\Sound\Creature\WaterElemental\Waterelementalloop.wav

I know wav files work, I would imagine an actual .ogg file would too. This is how silencing the obnoxious sounds of the mechahog/etc 'addon's work

WoW doesn't recognize .wav files since 4.0. This may either cause WoW to overlook your replacement and use the original, or still try to use it, but silently fail in playing the file.

Wow definately will read .wav files in terms of replacement, I currently use it both on live and on the beta client to supress the 'fizzle' sound from spellcasts and the gyrochopper idle noise, among other things. It isn't just failing silently either, as replacement of gun->bow sound works also.

And yes it's weird that PlaySound lost .wav access, but it does definately still work.

Basically, what you do is go to your wow folder, inside that should be a data folder.
In the Data folder you need to create a folder named Sound, and inside that one named Creature, and inside that one named WaterElemental, and in there you need to put a 0 length wav file named WaterElementalloop.wav
Basically you need to recreate the path based on the mpq, but DO NOT screw with the mpq at all, Blizzard allows file replacement of sound/etc files via this way, but screwing at all with the MPQ file WILL get you banned, as it allows you to screw with models and things that they do not wish altered.

Attached is a correctly made 0 length wav file that I use to mute things, feel free to rename it and put it where you need it.