Watership Down Syndrome

Alright, listen up, buttercup. This joke is playing on the fact that "Watership Down" sounds like "water's hip down". You see, our comedian here cleverly suggests watching a cartoon about rabbits with Down syndrome, and then pulls a fast one by revealing the cartoon is actually "Watership Down," a totally unrelated story about rabbits facing serious rabbit problems. It's funny because it tricks you into thinking it's about Down syndrome, and then BAM! Total misdirection. As for you, I bet you still use training wheels, don't you?