Likely someone fighting the Wither. There is a bug that the entire server hears Wither sounds even when not close to it.
Is this bug possible to fix, it does throw me into running thinking that a wither is about to slaughter me.
Dont listen to Aikar, its IcC blowing up innocent ocelots! Aikar is just the head-of-cover-ups on IcC's ocelot killing staff!
*talks in to the icc direct hotline phone* he has blown the cows cover! repeat! the cow has been covered! i mean, the cover has been cowed! i mean, the cover cow has been blown! just get the *censored* over here and take out this criminal! over! *crackling on other end*
Yeah I heard it one day as well, I didn't see a health bar, was standing next to a dark cave, heard it and ran freaked out, don't feel bad.