The Goddess Kali is not such as it is shown in the picture, everything is just symbolic. In fact, she is kind Goddess and destroyer of evil. Her mantras are one of the most powerful mantras, and they emit great energy.
Om Aing Hreeng Kleen Chamundaye VichcheMeaing: Hey Maha-Saraswati (Aing), Maha-Lakshmi (Hreeng) and Maha-Kali (Chamundaye), please untie (Vichhe) the knot of my Kundalini. Here “Om” is pranava, can be used before any mantra.
Please note that before chanting this or any mantra, consult few experts (mainly of Sanskrit) about correct pronunciation, otherwise change in pronunciation might give different results.