http://en.wikipedia.org/wiki/Nemertea#Proboscis_and_feeding
okay? not seeing anywhere in that article that says they leave their proboscis behind
the gif looks fake in general. like cheap horror movie cgi
but the fact that it shoots that thing out and then starts crawling off is what's really important. their proboscis is part of their body, it doesn't just come off like that
this is worded terribly then.
well, I'm not gonna disagree with that. but since I first read someone ask what it was I wanted to just say "fake"