Dark Invisibility, also known as Shadow Invisibility, is a dark power used by Jak during Jak 3 after exposure to a dark idol in the Great Volcano. Normally, the dark idol would have turned its victim into stone (as seen with the monk), but it translated into power for Jak. Dark idols transmit the invisibility power to Jak on touch which enables him to bypass automatic security systems such as sentries, though, Jak is only translucent, not completely invisible (which enables the player to see Jak).
Dark Invisibility is the only power that does not require Jak to turn into Dark Jak. It is also usable while in combat; enemies will still walk up to Jak, but will not attack him (with the exception of Marauders). After defeating the final boss, the player can buy a secret which enables Dark Invisibility on pressing 
.