it helps you to hear far away noise even if its half miles

a small anatomical pouch: as a : the part of the membranous labyrinth of the ear into which the semicircular canals open -- called also utriculus b : PROSTATIC UTRICLE

Their tentacles are not that long, reaching to lengths of 5 ft. But they are very poisonous.

If you mean in the inner ear, the cochlea which contains the Organ of Corti, and endolyph and perilymph, also the 3 semicircles of the labyrinth - the ampulla, the utriculus and the sacculus. Also the auditory nerve or VIIIth nerve

The part which is responsible for dynamic balance is the semicircular canals while the one responsible for static balance is the vestibule, which is primarily composed of saccule and utricle.