What is shiny gengar?

Shiny Gengar is a variant form of the Gengar Pokemon, a part-Ghost type Pokemon originally introduced in Generation I. Shiny Gengar is the result of randomly occurring genetic mutations, with its coloring and appearance different from standard Gengar. Instead of the purple hue of the standard Gengar, Shiny Gengar is primarily black with greenish-blue eyes and white mouth and claws. It first appeared in the sixth generation series, specifically in Pokemon X and Y, and was available via a special event distribution. In the seventh generation, Shiny Gengar returned as a special Halloween event in Pokemon Sun and Moon. Shiny Gengar is notable for being rare and highly sought after due to its unique appearance and limited availability.