Mohtrek

"These aren't just doubles--they are me. They are all me. Each one plucked from my past to aid me in the present. Instant army, ever loyal, and I can call on as many as I need. [...] Unfortunately, they--we--never seem to remember what we see in our own future."

- Bitil, BIONICLE Legends 10: Swamp of Secrets

The Kanohi Mohtrek was the Mask of Time Duplication.

Powers
The Kanohi Mohtrek gave its user the power to summon one or more past versions of themselves to the present. If any of the past selves were killed, the user would cease to exist, and an alternate timeline where the user did not exist would be created. When the past versions were sent back to their time, their memories of the future were erased. However, any damage to their bodies remained. Bitil chose not to summon copies of himself prior to when he entered the Karda Nui swamp, fearing that they might be mutated also. The amount of concentration needed to keep the past selves in the present increases with the amount of selves summoned.

Example Usage
Bitil used his Mohtrek against Toa Nuva Onua to summon a small army of his past selves in BIONICLE Legends 10: Swamp of Secrets.

Great

 * Makuta Bitil - Formerly wore shapeshifted version; now deceased.

Trivia

 * Toa would not usually wear a Mohtrek, as they found its power immoral by messing with the flow of time and it was associated with a Makuta.
 * Bitil considered this mask a curse as much as a blessing because he would often find himself with injuries, with no idea how he had obtained them.
 * The Mohtrek worn by Bitil was created out of protosteel.
 * As a side-affect of being worn by a shapeshifter, whenever Bitil shapeshifted, his Mohtrek would change with him.