Incidentally you might want to look into a condition called wandering bladder.
Why?
Oh no reason, no reason at all.
The Route Of All Evil?
That’s my guess. Very end. When Cubert says he wants to be “just like” the professor.
That’s a good guess but nope!
Is it the one where he learns how to fix the ship and finally understands the Professor?
A Clone of my Own
When the Sunset Squad Robots take the professor off to the old people world due to him turning 160 years old. Fry, Leela, Bender, and Qubert rescue him and along the way Qubert finally reconciles with the professor.
It’s the Near Death Star, actually.
Wait, something I never thought of. Why do they have different skin tones if they are clones?
I hadn’t noticed either but I’m guessing the prof spends a lot of time inside. Kids play outside and get tan?
Maybe it’s the age