Favorite Planet Killers

Death Star.
 
The runner up would be the Planet Buster from Spore, if only because it’s the only other one I know by name.

Ea.
 

 
That is all.

hmmm The thing that destroyed Spock’s home in Star Trek. The movie where there is time travel.

@igotnopicks
 
You mean the Black Hole creating Red Matter?
 
Personally, I like to believe it doesn’t create Black Holes, it creates a wormhole to a Black Hole (it creates a wormhole to the strongest gravity well within a certain range, and that happens to be the one at the centre of the galaxy).
 
@5kmoe
 
So… Missingno?

King Ghidorah.

@Vlakc  
You sir, you have won the game.

I completely forgot about the ending to the expansion…  
 
Planet? Try galaxy.

Getter Emperor

@trashboat
 
I’ll see your Getter Emperor and raise you…
 

 
Tengen Toppa Gurren Lagann

The Eclipse Cannon. It took out a chunk of the moon and it didn’t even have all seven Chaos Emeralds yet.  
Arguably, the Space Colony ARK itself could count as a planet killer, seeing as how Professor Gerald reprogrammed it to crash into Earth once all seven Emeralds were installed.

The Blind from Green Lantern.

If you played the game, you’ll get this. Nice job breaking reality and everything else, heroes!  

Majin Buu. While all of the major DBZ villains (and some of the heroes, too) are capable of destroying the world, Majin Buu is the only one who actually does it. He actually does it twice, causing a Class 3a Apocalypse and a Class X Apocalypse.

@Sonic the Hedgehog  
Well, Frieza destroyed at least two planets, and there are more examples in DBZ, but I was using only Earth as an example.

 

 

 

 
And finally