Mountain lions (Puma concolor) are cats, OK. Cats (Felis silverstris) are cats. So a contest between them is a fair fight, yeah? Well, that seems to be the logic applied by one domestic feline with more courage than brains, who is quite happy to go paw-to-paw with a mountain lion – at least as long as there is a pane of glass in between. It's not the size of the cat in the fight...
Mountain lions can weigh up to 220 pounds (100 kilograms), and have experience actually killing their prey, unlike pampered moggies, so while we admire the cat's bravery, we're thinking it has good reason to be grateful for the glass.
As Tom Mabe, the maker of the video, suggests in the comments, “I want to get a sponsorship from Pella Windows or some other double-pane window company.” Secretly, his friend's cat probably agrees.