Hi everyone,
Reverse SEO is the process of removing sites other than your own from the search result. Reverse SEO is the technique that helps to improve own site's ranking and decrease the competitor's ranking. To do this one has to do huge spamming of the competitor's site with lot of links to other sites. So Google thinks that this site is trying get ranked by huge spamming and so the site gets penalty and disappear from the search engines completely.