Cloaking is a spamming search engine optimization technique
Cloaking refers to the practice of presenting different content or URLs to users and search engines. Serving up different results based on user agent may cause your site to be perceived as deceptive and removed from the Google index

Cloaking is a black hat SEO technique, which consists of showing search engines other content than the one shown to users. The purpose of this technique is to deceive search engine with regard to the relevance of a web page for one or more keywords. The content is delivered based on IPs or user agent.