Copy another person's power, abilities and magic
Be affected by a power or be in physical contact
The possessor can copy any powers that is used on or against them. When Prue used Telekinesis directly on Matthew Tate, he was able to mimic her power and then become immune to it, leaving her defenseless when using her power directly on him.
The user can also copy passive powers such as Premonitions. However, the user would have to hold onto their target while they are using their power. When Matthew touched Phoebe, she received a premonition, which allowed him to mimic her power and experience the same premonition. He was later able to use her power to get a premonition off Melinda Warren to track down Prue.