From the article:

Piranha 3D had one of the greatest severed penis scenes in science fiction movie history — so how does the sequel, Piranha 3DD, follow that? With something so horrible and wrong, you may require several years of therapy after watching the above video. It's Not Safe For Work!

Seriously. Years of therapy. Or possibly just watching a hundred cat videos to clear the nastiness out of your brain.

...it almost beats a zombie rat and a zombie penis fighting in Beyond Re-animator. I think what makes it so ridiculous is that it combines Alien-style pregnancy horror with vagina dentatas, monsters and very sharp knives.