Expanded Possession( Ghostwalk, p. 31)
You can ride or possess an additional type of creature.
Ghost Ride (Gh) ,
Choose one type of creature, such as giants. You may use any feat from the path of the dominator on that sort of creature as if it were a creature of your own type. For example, a human who selected this feat and chose giants would be able to use Ghost Ride on humanoids or giants. Choosing a creature type that is not affected by mind-altering abilities (such as constructs, oozes, and undead) has no effect.
You can gain this feat multiple times. Each time, you choose a new type of creature to be affected.