Hello everybody, this is Maniac4Bricks. I set a goal for myself in 2020 to build minimum one new Bionicle MOC for the year. After months of struggling complex figure designs, I finally accomplished it on July 6, 2020.
Inspired by a screenshot from Bionicle: Legends of Mata Nui, from @BionicleBot on Twitter, I quickly jumped on the opportunity to create it in authentic Bionicle pieces. To my satisfaction, reverse-engineering the build and gathering parts was stress-free; I finished the model 2 days after the original inspiration.
Here is the parts list (alternatives can be found in subsequent photos below). The most uncommon parts to obtain would be the green Pakari found in Mask Packs and the green Throwbot/Slizers foot from Amazon/Jungle. For a more accurate model, I would recommend swapping the 2 black Technic liftarms on the bottom right for dark green ones. While I do own them, they were buried in my collection at the time of photography. I might update that look later for accuracy.
Here’s a breakdown one-step instruction to building the MOC. The neck fits in between the axles on the liftarms, secured on top by the second liftarm and head/mask as a shell.
Alternately, you can also use ball joint pieces for shorter limbs. The Technic cam piece doesn’t exist in dark green so I used Bohrok eyes as the next best piece on hand. And the photo doesn’t make clear if the body should be black or dark bluish gray, so I’m showing what works in both options. The neckpiece can also be replaced by another Technic ball joint followed by a Turaga handpiece with an axle at one end, axle hole on the other. The Technic ball joint may appear green in the original screenshot, so try the tail of Alien Puppycorn.
And voila! However you enjoy this build, there are four options for the Sea Turtle.
Back and bottom poses.
And finally, comparing the Sea Turtle to a Toa Mata. While I have not played the Legend of Mata Nui game, this feels like an appropriate size for a creature in Bionicle games, reflecting on past Rahi appearances in console games over the years.
This is a small MOC but a big accomplishment for me personally, and I’m happy to have a medium to share it step-by-step with others to not only enjoy but also get to build themselves how they like 
Have a wonderful day everyone!
- Maniac4Bricks