70792 Skull Slicer is a 71 piece BIONICLEset that was released in summer 2015, retailing for $15. It includes the titular Skull Slicer, as well as Lewa's Golden Jungle Mask, which is being drained of its power.
This is a description taken from LEGO.com. Do not modify it.
Get 4-armed and dangerous with the Skull Slicer!
Patrol the ruins of the ancient arena with the menacing Skull Slicer! This ancient champion has been animated by the dark magic of the Skull Spider Mask, fusing him with his razor-sharp hook blades. Create fearsome combat poses and turn the wheel on Skull Slicer’s back to activate the 4 battle arms all at once. Use the hook blades to rip off masks and pick them up with the mask grabber. Any LEGO® BIONICLE® hero wanting to pass through the arena will have to get past this wicked warrior first!
Features a Skull Spider mask and mask pop-off trigger, shell with cool metallic-effect chest decoration, 4-arm battle function, 3 hook blades, mask grabber with translucent orange chain and hook, silver-colored bones, translucent rib cage and posable joints
Turn the wheel to activate all 4 battle arms!
Rip off hero masks with the hook blades!
Pick up masks with the mask grabber
Pop off the Skull Spider mask!
Durable design for intense action play
Stands over 7” (20cm) tall
Combine with 70791 Skull Warrior and 70793 Skull Basher to create a multi-headed warrior using building instructions available online at LEGO.com/BIONICLE/bi
Instead of using a new mask like the other villains from summer 2015 BIONICLE wave, he reuses a silver Skull Spider mask. This is because Skull Slicer is under the influence of the Lord of Skull Spiders.
In the July-August LEGO Club magazine, it was revealed that he was once a champion of the Okoto arena, but was apparently took control of by the Lord of Skull Spiders, thus turning him into a skull creature.