Onyxx (Sidney Green) is a fictional mutant appearing in comic books published by Marvel Comics. He first appeared in X-Men, vol. 2 #171 (August 2005), and was created by Peter Milligan and Salvador Larroca.

Fictional character biography

As a child, Sidney Green lived in various foster homes and orphanages, unable to find acceptance because of his crude behavior and chronic bedwetting. This was cured after his mutant abilities activated, transforming him into a four-eyed golem-like creature. Subsequently, Sidney becomes a student at the Xavier Institute as Onyxx and joins Gambit's training squad, the Chevaliers. He develops a crush on fellow student Foxx, who is later revealed to be a disguised Mystique. Sidney is one of 198 mutants who retain their powers after the Scarlet Witch depowers most mutants on M-Day. He is later killed by Wither before being resurrected after the establishment of Krakoa.

Powers and abilities

Onyxx has a craggy granite body, which gives him superhuman strength and durability. He also possesses an additional pair of eyes, but it is unknown if these serve any special purpose.