Activation/deactivation is the ability to start and stop mechanical and biological systems, including abilities.
- Matt Parkman Jnr has this ability naturally, in World 2, World 3, World 8 and World 11.
- Abbie Gray has mimicked this ability from Matt Jnr.
- Noah Gray has also mimicked this ability from Matt Jnr.
- Peter Petrelli has absorbed this ability in World 2, in World 5 and in World 8.
- Ellis Thompson has this ability from the formula.
- Jessica Sky Petrelli has absorbed this ability from Matt Jnr.
- Robert Max has also mimicked the ability.
Matt has used the ability extensively to activate and deactivate objects around his home. He has also once used it to activate an ability, Hiro's, but he is yet to deactivate one. He was shown requiring touch to activate and deactivate, but it is unknown whether this limitation is merely due to his young age, and could possibly be overcome in future. In World 2 it has been stated that he can also theoretically deactivate a person's heart or brain and therefore kill them, but he has not displayed this aspect. It is unknown whether he possesses this aspect in the other three worlds.
Abbie has similar limits to Matt in World 2.
Noah also has similar limits to Matt and his sister.
Peter has similar limits to Matt and the twins in World 2. He has not yet displayed the ability in World 5, but would have similar limits to Ellis. He has not displayed it yet in World 8 either, but would there have similar limits to Matt.
Ellis has used the ability to activate and deactivate several machines and pieces of technology. He often uses the deactivation aspect on raids, deactivating alarms, electronic locks and CCTV cameras. He has also deactivated an ability a few times, and once activated an ability which had been lost to ability absorption. This appeared as white sparks which flew from his hand and landed upon Peter, activating his ability. None of the other uses have appeared thus, but this could be because he had physical contact in all other cases. Although he is currently unaware of it, he could also trigger manifestation of a latent ability, or force a person to access their ability, both by using a similar aspect as that which activated Peter's empathic mimicry . He will never be able to use the ability to kill, like Matt will be able to in World 2.
Jess is yet to display this ability. However, she mimicked the ability from Matt Jnr, and therefore ought to have similar limits to him.
Robert would have similar limits to Matt in World 8.