There's another video I saw with a mouse being dropped into a tank of piranhas. I'm thankful this one was much shorter than it.
Recalling the experience of seeing the piranhas video: At first I thought it would be awesome, however, it soon turned depressing and even horrific because the mouse didn't simply get eaten immediately, the mouse almost looked like he had a fighting chance if there were a way out of the tank. Even when he was missing several limbs, he struggled to survive – kicking away the piranhas as best he could. After a few minutes, I was no longer hoping to see a feeding frenzy, but hoping to see the struggling thing survive.
I'm no vegetarian – far from it – but I find it hard not to pity these feeding mice sometimes because after seeing something like that, that they have an incredible tenacity and will to survive, even when the situation is hopeless.