Seeing Eljay’s review of the Bionicle pens reminded me of the Bionicle Minifigures that I made, so I figured I would showcase them here. I used a technique involving what Brickset calls balls and ball cups. LEGO parts Technic-Beams-W-Ball-And-Ball-Cup | Brickset
When you place a ball on a Minifig torso, and attach the ball cup to the back of it, you can attach a 2015/2016 Bionicle mask onto the ball cup. The mask’s hinges click on like they do on the new mask stands in the Ekimu vs Skull Grinder set. I used a lime green ball so it can work as an eye stalk.