Snowball (episode)

Plot
As Brain is preparing for his latest scheme to take over the world, he is interrupted by the arrival of his old friend from before he become smart, a genetically altered hamster named Snowball. However those days are long gone, as Snowball has also become a genius, and the two have a race to see who can conquer the world first, but Snowball proves to be a better match than The Brain.

Quotes
The Brain: While I developed my plans for world domination, Snowball had only evil in mind.

Pinky: Brain...

Pinky: Troz!

Pinky: it's Zort in the mirror! Troz!

Snowball: What do you want?

The Brain: My friend, and my world.