Emily Brown, known most broadly as Auntie Em, is an episodic character on Once Upon a Time.
Before the Curse
When Em's niece Dorothy returns from the magical land of Oz, her family refuses to believe her and try to have her committed to a mental institution. However, Em supports her niece's stories and prevents this from happening by giving her a place in her home. Dorothy loves her aunt very much, even receiving a dog named Toto as a present, but, unfortunately, Em passes away soon after. ("Ruby Slippers")
Em makes a "fatal" mistake. ("Ruby Slippers")
After Em dies, her soul travels to the Underworld where she owns her own diner called Auntie's Chicken & Waffles. One day, a group consisting of Ruby, Emma, Snow and Regina come looking for her, explaining that her niece Dorothy is in trouble because she's been put under a sleeping curse and needs a kiss of true love if she has any chance of waking up. Since Em can't perform the kiss in person, it will need to be bottled. However, before her kiss can be captured, she is suddenly struck by a strange magic. As it turns out, Hades - the Lord of the Underworld - spiked her soup with some water from the River of Lost Souls. This causes Auntie Em to be reduced to a puddle and her remains are later poured into the river itself, meaning she's condemned to an eternity of misery. ("Ruby Slippers")
However, after Hades's death, it's revealed that the River is now escapable -- heavily implying that her fate isn't permanent after all. ("Last Rites")