Fratricide: Do whatever it takes to survive.

Some of you may not know this, but there was once a companion in Portals, he was called the Weighted Companion Cube.

*sniff*

I have bad memories, we got into a fight, and he fell into a giant flaming pit.

Many others miss the Weighted Companion cube so much they're using the lost and dark art of papercraft to bring him back.

Download here

Random thought: Valve should market a small plastic Weighted Companion Cube, as demonstrated here, it'd make a wonderful friend with the big daddies.