Mama Jonas Blue feat. William Singe Download 'Mama' on iTunes
This dog is let off its lead and chases a herd of Red Deer around Richmond Park in London.
The owner understandably goes crazy, shouting at the dog to stop, but to no avail.
The dog continues to chase around 30 deer and even leads them toward a road, which luckily they manage to cross safely.
It's become so popular that even a number of hilarious spoofs have been made...