Mimicry

Mimicry is the rare and extremely powerful ability to copy any power, ability, or magic and use it as your own.

This was not one of the Warren gifts until Madison Taylor, ancestor to the Halliwell line, passed it on to her son Alexander; and he passed it on to his youngest duaghter Lydia. This power is bestowed on members that are destined to become Guardians, the only exceptions are Alexander and Lydia. Since then Lydia declared it that this power be bestowed upon to the fourth child only

List of Users
Witches
 * Alexander Warren
 * Lydia Warren
 * Drake Halliwell
 * Rex Halliwell
 * Prue Halliwell