Empathic Mimicry

Empathic Mimicry is the ability to duplicate abilities of other evolved humans.

Information
Empathic Mimicry is an empathic ability that allows the user to copy the abilities of other evolved humans. The user gains full use of copied abilities, including strengths and weaknesses. According to  Peter Petrelli in Distractions, in order to use a copied ability when the donor was not present, he had to remember how that person made him feel. While amnesiac, Peter was still able to use copied abilities, even without memories of the person from whom he learned them. He also has demonstrated the use of abilities absorbed from people that he wasn't aware had any, meaning that an absorbed ability is triggered when Peter feels an emotion linked to the person he absorbed the ability from, rather than remembering the actual person.

The user does not have to see abilities in use to absorb them. In  The Hard Part, Peter gained used of Ted Sprague's Induced Radioactivity, despite the fact that Ted has not used it in his presence. Also, Peter absorbed Niki Sanders's Enhanced Strength and D.L. Hawkins's Intangibility in How to Stop an Exploding Man, during his fight with Sylar. However, Peter has never properly met D.L., but gained his ability nonetheless. If this is so, he may also have absorbed Molly Walker's Clairvoyance and Micah Sanders's Technopathy, but he has never displayed these abilities.

Peter would typically absorb abilities involuntarily, meaning he was unaware of some abilities he absorbed.

Users are able to absorb both natural and synthetic abilities, as Peter copied  Nathan Petrelli 's synthetic Flight  prior to  Genesis  and Niki's synthetic Enhanced Strength in  How to Stop an Exploding Man.

Weaknesses
Empathic Mimicry can be lost to Ability Absorption. This also causes the user to lose all of their copied abilities.

As revealed in an interview, users of Empathic Mimicry are unable to copy abilities that another user of Empathic Mimicry has copied.

According to Mohinder Suresh in The Fix,  it could be dangerous for Peter to get near someone with an "unstable" ability.

According to  Milo Ventimiglia in a behind-the-scenes video, Peter passed out at the end of Fallout  because he was overwhelmed by all of the abilities he has been absorbing.

Notable Empathic Mimics

 * Peter Petrelli (lost)
 * Peter Petrelli (Explosion Future)
 * Peter Petrelli (Outbreak Timeline) (deceased)
 * Peter Petrelli (Exposed Timeline) (deceased)
 * Arthur Petrelli (absorbed, deceased)

Trivia

 * Despite Peter using multiple abilities simultaneously on several occasions, it was stated in an interview that Peter only has access to one ability at a time.
 * In special feature "The Writers Forum" found on the Season 3 DVD, writers Tim Kring, Adam Armus, and Aron Eli Coleite reveal that Empathic Mimicry and Ability Absorption are actually different versions of the same ability.