The LEGO Sonic the Hedgehog Knuckles' Guardian Mech Building Toy Set 76996 is a building toy set that features Knuckles' Guardian Mech. It is a complete set that includes LEGO bricks and instructions for building the mech. The set is designed for fans of Sonic the Hedgehog and those interested in animals. The set is part of the LEGO Building Toys and LEGO Complete Sets & Packs categories.