For most of the 19th century, Marie Laveau practiced Voodoo and cared for the sick. For her works, Marie won the love and adoration of the people in New Orleans. When she became too old to continue, Marie Laveau II, her daughter, took over her public responsibilities which inadvertently fueled speculation she was immortal. However, Marie II led by fear rather than love. When things got out of control, Marie used a locket of Marie II's hair to turn off her heart. Before she died, Marie II swore revenge. As a result, Marie remained on the physical plane as a ghost and awaited her daughter's return.
Over a 100 years later, Marie II's ghost finally manifested. Marie couldn't bring herself to destroying her daughter. A friend, Mr. Thibodeaux, suggested she hire the Ghostbusters. A few weeks later, the Ghostbusters arrived in New Orleans and accepted the case. Marie was interested in Egon Spengler, in particular, and his use of the P.K.E. Meter. She imparted advice to Egon that love was important in life and gave him powerful Gris-Gris for when he was ready to live. The next morning, the Ghostbusters presented the Trap holding Marie II to Marie. She felt peace at being near her daughter one last time and blessed the guys for their success.
- Egon asserts Marie Laveau would be well over 200 years old, in reality her age has been in contention. Some posit her birth year as 1794 others, 1801.