Kali

Great Aunt Kali is the great aunt of The Grim Reaper. Like her nephew and the rest of her family, Great Aunt Kali is an 'undead, talking magical skeleton', her bones have a green tinge to them and she has snakes growing out of her skull (similar to the Gorgon Medusa).

Kali is the aunt to either one of Grim's parents, and the aunt-in-law to the other. Kali may also possibly be the sister of Granny Grim, Grim's grandmother--but the relation is never verified in the series run, only by the virtue of their relation to Grim.

History
In her sole appearance, in Recipe for Disaster, after Billy ate all of the 'People scout' cookies -- and after Mandy refused to let Grim cut them out of Billy -- Grim proposes that they bake their own cookies to replace the supplies that Billy ate, and volunteers his great aunt's famous recipe to guarantee that their troop will win an inter-troop competition over who sells the most cookies and confections.

After their scout troop wins with Grim's aunt Kali's special recipe, Kali is invited to the award ceremony. When asked about her secret, Kali reveals that the special ingredients are night crawlers, mush crickets and dung beetles. For a tense moment everybody stops eating the cookies in disgust, but the cookies are so irresistible that everybody keeps on eating them -- even Mandy.

Trivia

 * Kali is named after the Hindu death goddess