Emily Kristal Mayonnaise is character appearing only in the Disney series. She's very kind, understanding, eccentric, and she gets highly into any book she reads to her students.
In the Disney episode "Patti's Dad Dilemma", it is revealed that Emily has become Chad Mayonnaise's girlfriend, and Patti was unaware of it until she found a note from Emily to Chad in the trash with only Emily's initials "E.K.". At first, Patti believed that E.K. was Edwina Klotz, so she asked Doug to help her spy on Chad only to find that Chad wasn't dating Edwina but Emily Kristal. Patti was miserable knowing about her father's relationship, and she had a breakdown when Emily came over for dinner. After a talk with Patti, Chad said that he planned to keep seeing Emily and wanted his daughter to feel good about it, and Patti was okay with her father dating her teacher.
In the series finale "Doug's Marriage Madness", Emily got married to Chad and she became Patti's stepmother.