耿鬼（日文：ゲンガー）是神奇宝贝系列登场的721种虚构角色（怪兽）中的一种。

耿鬼为幽灵系的影子神奇宝贝，有如幽灵般的身体，是鬼斯通的进化形，进化后与之前不同的是多了一对腿。较常使用的绝招有催眠、隐身等。身体颜色主要由紫色组成。耿鬼为鬼系及毒系的神奇宝贝，全国图鉴编号为094。

Gengar, known in Japan as Gangar(ゲンガー,Gengā), is a Pokémon species in Nintendo and Game Freak's Pokémon franchise. It is a Ghost/Poison type Pokémon. Designed by Game Freak, their name is both the singular and plural name of the species. First appearing in Pokémon Red and Blue, they later appeared in subsequent sequels, spin-off games, related merchandise, and animated and printed adaptations of the franchise. In animated appearances, Gengar are voiced in Japanese by Kōichi Sakaguchi and in English localizations by Ted Lewis.