The depiction of Goddess Kali with her tongue out is tied to the story where she steps on Lord Shiva in a fit of rage and then sticks out her tongue in embarrassment and realization.

The color black is symbolic of absorption and transformation. Maa Kali being black signifies her all-encompassing nature and her ability to absorb all colors, symbolizing ultimate reality.

Yes, you can keep a Goddess Kali statue or image at home, especially if you are drawn to her energy. However, it's advisable to do prana pratishta of the statue by Hindu priest to properly install maa kali into home temple/ sacred altar place.

Worshipping Goddess Kali at home can be done through various rituals, including lighting a lamp, offering flowers, blood and chanting Goddess Kali mantras. It's always best to consult with your Hindu priest for specific guidelines on Pooja as per your desires and Wishes.

The most Popular chant for Goddess Kali is the Kali Beej Mantra:

"Kreem Kreem Kreem Hreem Hreem Hoom Hoom Dakshine Kalike Kreem Kreem Kreem Hreem Hreem Hoom Hoom Swaha."

It is believed to bring closeness to Kali and is often used in various rituals.

No, Goddess Kali is not evil. She is often misunderstood due to her fierce appearance, but she is a symbol of liberation, protection, and transformation.