Why is a Damaru attached to the Trishul that Lord Shiva carries? What does that Damaru signify?
Shiva is often described as cosmic dancer and a great musician. Shiva's Tandavam is the cosmic dance and his Damaru (a small hourglass shape drum) represent the cosmic sound. It is said in Shiva Mahapurana that
The sound from damaru often is interpreted as the Pranavam and represent the *Shabda Brahma*n. Pranavam or OM is supposed to the precursor to all human languages.1
There's a very beautiful strotam which mimics the sound produced by damaru called Shiva Tandava Strotam by creating a rolling effect. The first couplet is —