This would become massively annoying, but it is also a really cool office toy called Terry Turtle. In short, he is a motion-activated turtle who pops out of his shell to tell you a number of profane things.
The video shows it all--I know I am a child to find him funny, but I can't help it. I am properly giggling to the video, please don't judge me.
(UK people: Doesn't he sound like Russell Brand at the end?)