Type-27 hologram

The T-27 Responsive Holographic Form Emulator, often shortened as "Hologram" or "T-27 Decoy package", is a piece of UNSC military equipment developed from Covenant technology. It is utilized by SPARTANs.

Overview
The emulator is reverse engineered from Covenant technology and is later integrated into the MJOLNIR Powered Assault Armor. The emulator creates an holographic copy of the user and can be commanded to move to certain locations chosen by the user. It is often used to deceive enemies.

List of appearances

 * Halo: Reach
 * Halo 4