Google Penguin is a filtered mechanism or algorithm, which find out the Google web spam search results. Because Google usual system can not deduct those spammy results. In simple words, Google Penguin find out those sites who are performing spamming activities in search engine. If Google Penguin filter find your website spammy so it would be penalized across Google search engine.
As we know that, Google Penguin 3.0 was updated in 2014 October and on that time, Google Penguin penalized so many website which was free after two years in search engine again. But right now the strategy is completely different because now Google Penguin 4.0 coming with real time re-crawling or re-indexing, means if the webmasters doing the changes after crawling and revert back their changes to spam then this real time will check the pages constantly and if they found any spamming so it would be penalized.
Google Official Said;
With this change, Penguin’s data is refreshed in real time, so changes will be visible much faster, typically taking effect shortly after we re-crawl and re-index a page.
They also declared;
Penguin now devalues spam by adjusting ranking based on spam signals, rather than affecting ranking of the whole site.
Which means Penguin will impact on specific pages of the site not the entire site like before. Google Penguin 4.0 is not fully live in real time yet and I think it will take slightly time to come live (Couple of days from now).
Now according to this Google official statements, if your particular web pages is under spamming position so it will not put impact on whole site, so your entire website will not be punished for this single page on your site. I personally found this Google Penguin update very useful for webmasters from various perspectives.