Embryo Princess is a princess who looks like a fetus in a pink bubble and appears briefly in "What is Life?," "Loyalty to the King," "The Lich," and "Jake the Dog." In the episode "The Lich," the gem from her crown was taken by Finn and Jake with a pair of tweezers as she slept. She apparently has some sort of telekinetic power that enables her to create a bubble around her that resembles an amniotic sac-like ball. Natasha Allegri came up with the idea for Embryo Princess.
Embryo Princess looks like a human fetus. She has a golden tiara with a magenta stone in it, similar to that of Princess Bubblegum, Slime Princess, and Princess Princess Princess' monster head's tiara. She doesn't seem to have any clothes on, and her purple veins are visible through her face and her body. She also has a jelly-colored aura surrounding her human-like body.
Her phone resembles a small pink cube, and is a very strange looking phone.
According to Pendleton Ward, if Finn were to marry any princess, he'd marry Embryo Princess, though this was most likely a joke.
She had "X"s over her eyes in earlier designs.
Her tiara resembles Princess Bubblegum's, which has the ability to block the telepathic power of the Lich.
Normally the gem in her tiara is red, but in the episode "Jake the Dog," her gem is light blue.
Much like most minor princesses, Embryo princess has had many accidental changes in her appearance throughout the series. In the episode "What is Life?," her telekinetic bubble was blue and round when it is supposed to be wiggly and pink. She also had no gem on her crown. In the episode "Jake the Dog" her gem was light blue when it was really supposed to be magenta.