Old Lady Princess was meant to marry Ice King in the episode, "When Wedding Bells Thaw." When Ice King tells Finn and Jake that he is getting married, she is seen riding in a wagon with a bunch of female penguins who were supposedly taking her to her bachelorette party. She was cursed by an engagement ring given to her by the Ice King. The ring was spiky, magical, made of ice, and it tricked her into thinking she was in love with Ice King, which was not the case. She was then freed from the curse at the wedding, when Jake took off her engagement ring. Then, the Ice King accidentally married Jake instead.
Old Lady Princess is a short, wrinkly old woman. She has light green skin and lavender hair. Her crown has a blue bow on it and is gold like most other princesses' crowns. She had large, shiny eyes when being controlled by Ice King, but when she was freed, her eyes were very little and white. She also wears a dark purple dress with lace and light blue trimming on the bottom and waist.
When Old Lady Princess says, "Thanks, man," after Jake saves her from falling (herself still inside her own eye), the bars in the eye she is trapped inside of change from ice bars (also seen in "Prisoners of Love") to prison bars.
It seems that Old Ladies are not humans, but actually a race of their own.
After the Ice King "marries" Jake, she is still seen with big eyes when Ice King is looking at Finn and Jake.