Sonikku is an Echidna who Sawneek snatched from the future when he was very small. It is presumed that he is the "mirror world" version of Knuckles. Sonikku likes to be called Knuckles but everyone calls him Sonikku. He is friends with Sawneek and joined him in his later shames.
Death and Resurrection
Sonikku was run over and killed while cheering Luigi on in Mario Fart SD but was brought back to life. He later died again and was resurrected, died again, was resurrected again, and so on and so forth.
The first time he was resurrected, he turned evil and ended up wearing a pink skirt; then, he was run over by somebody's Mario Kart vehicle again. He later came back to life, wearing an idiotic outfit and proclaiming he was called Enerjak. This time, he was killed by Knuckles for being "an offensively lame poser".