Matal Knackles is the robotic version of Knackles Enchilada invented by Dr. Robuttnik. He has all of Knackles' regular powers but MOAR. For example, Matal Knackles is a better bug catcher than Knackles, and can swim better than him. But that doesn't matter because swimming rusts Matal Knackles.
Matal Knackles is sooper-stupid, so he always botches up Robuttnik's plans. He was later repaired by Dr. Aggmen to become a genius, but somehow he still sucked just as much as before.