The cyclopskin first appeared in the first edition Monster Manual II (1983).
The cyclopskin appeared for the second edition as a type of giant in the Monstrous Manual (1993). The cyclopskin was detailed in Dragon #254 (December 1998), in the "Ecology of the Cyclopskin".
A cyclopskin is a large humanoid with a single red eye, which inhabits wilderness areas, particularly favoring rocky places and caves. They typically live alone or in small bands, shunning other creatures except for prey or slaves.