The two-headed daughter of the Hydra, Peri and Pearl are twin sisters Two heads and a serpentine tail allows doll to stand on her own Glow-in-the-dark accents are creepy cool They may have their own minds but not their own bodies Dive into the Monster High Aquatic Adventure with Peri and Pearl Serpentine When the Monster High ghouls get pulled into the school pool, they find themselves in deep water -- the crystal blue water of The Great Scarrier Reef. The wild underwater wonderland is not only the home of Lagoona Blue, daughter of the Sea Monster, but is also home to a whole new cast of characters with freaky flaws of their own -- like two-headed twin sisters Peri and Pearl Serpentine! Twin Sisters Double the Freaky Funny Fun! If there is one thing these two sisters and beasties can agree on, it’s that great minds do NOT think alike. The twin daughters of the Hydra find that sharing one body is no “fin and games” when you can’t see eye to eye! But two heads are sometimes better than one, and these sisters know how to laugh and always stand together -- to add to the effect, their tail is designed so that the Peri and Pearl Serpentine doll can stand alone for a cool display.