Superman: The Animated Series – Stolenmemories

Brainiac, once Krypton’s all-knowing planetary computer, comes to
Earth as part of his information-gathering trek across the galaxy.
But, as Superman discovers, Brainiac’s intent after gathering the world’s knowledge is to destroy the Earth.  

Media by Amazing Spidey, Bird Boy
Review by Bird Boy

Voices:
Tim Daly as Superman/Clark Kent
Dana Delany as Lois Lane
Clancy Brown as Lex Luthor
Christopher McDonald as Jor-El
David Kaufman as Jimmy Olsen
Lauren Tom as Angela Chen
Corey Burton as Brainiac
Victor Brandt as Professor Hamilton
Townsend Coleman as Programmer
 

It starts out with Luthor making "first contact" with the second alien to arrive on earth, Brainiac. Later on at what looks like a Metropolis
United Nations, the people are bawling out Luthor for making contact with a potentially hostile alien. Luthor retorts, saying Brainiac has offered information about other worlds, their technology and more in exchange for information about earth. In the end, Superman goes to meet with Brainiac to see just how "hostile" he is. What Superman finds is what appears to be a "data collector", as he has hundreds of tiny spinning orbs full of planet information and even a orb for Krypton.
Superman puts the Orb in the palm of his hand and learns about the final days and more.

Back at his apartment, Clark dreams of the orbs, and sees things he didn’t see before–that Brainiac was the cause of Krytpons destruction.
Before he can talk and convince Luthor that Brainiac has no intention of
"sharing" anything, he begins a upload link between Lex Corps computers and Brainiac’s ship. After the link up, Brainiac locks out Lex, disabling all missile systems that are pointed at his ship and all of
Lex Corps computer uplink systems.

In the end, as always, Superman beats the snot out of the bad guy and wins, with Brainiac, his ship and all of the planetary orbs, except
Kryptons, explode (the result of Luthor’s now-functioning missiles), supposedly "deleting" Brainiac from existence…or is he really gone?

All in all, a very very VERY good episode, plenty of action, great animation and great dialogue make this a killer episode that’s definitely in my top 10 list.