A strange story:
Apparently, the Ontario Science Center set this piece of footage loose on youtube in the hopes of that it would go viral, so as to help promote an upcoming exhibit. Well, it has received 127,000 or so views, so I suppose that bit worked. On the other hand, you don't expect a respectable org. like the science center to be involved in a hoax, now do you? And since the center is owned by the province of Ontario (you can see that from the contact info on their news release here: email ends on.ca), I suppose that means that the Ontario Government is now playing pranks on its citizens.
As for the unicorn, well, it looks like its being towed across the screen on a set of wheels, so definitely not the real thing.
PS. I notice that the show this is an advert for--Dragons, Unicorns & Mermaids--has been running since the first week of the month. I haven't heard of it, and I pay attention to such things. So maybe the viral campaign was a bit of a flop.