Pixiv dictionary entry
Watching the video will not help you understand the punchline any better, fyi.
My philosophy with this series is to avoid putting in tl notes if it's still funny without context. Most of the jokes are non sequiturs anyway. But in this case, it's totally impossible to google ゑなる in English and get proper results (not to mention, this video's notoriety will probably fade within a few months even in Japanese).