Polymorphism refers to any creature or device that has the ability of changing their shape or form somehow. This can be as simple as altering some slight features of one's appearance, or completely shifting into new race altogether.
appeared in the Sound Chaser's natural form - a pyramid shaped space/time vehicle - and also appears as a large gothic mansion known as The Rhoades Mansion. In addition, Sound Chasers also possess mechanics that can change the shape and form of its inhabitants. This is used in Serial 2 "The Aslanders" and Serial 4 "The Trouble In Paradise" to turn Jon Ommandeer and Rael Ommandeer from Feral Deers into Manages. Over in Serial 11 "The Planet of Genetic Misadventure" Sir Jon uses Rociante to transform Christine James from a human into an Anthropomorphic Fox. This process is described as being complex, going so far as to change one's complete structure right down to their DNA, and as we see with Christine James' transformation, is extremely painful if undergone while conscious.
Blair Montgomery has also shown the power to transform other creatures into other forms.
Tigers Kitten, who plays the character of Melaine in Spectral Shadows, is described as being a tiger/orca/bat hybrid, but the power for TK to shift into any of those three forms suggests polymorphic powers. It is currently unknown if this trait will be utilized in the saga itself.