8 Video Game NPCs You Would Die To Protect
5. Weighted Companion Cube - Portal

I'm sorry, what do you mean, "It's just an inanimate object"?
This is no mere cuboid with a heart printed on, pal, this is quite literally your only source of comfort within the harsh confines of the Portal games, and when you're alone - testing forever of course - you're going to start looking for friends in the strangest of places.
If you need a clear cut example of how much the Weighted Companion Cube means to the player base, then you don't need to look at the huge amounts of plushies Valve shifts of the box buddy each year, but of the sheer amount of effort that fans went to trying to find out ways in which to complete levels while still keeping the Companion Cube safe.
Valve took something, a literal box with a heart on it (that may or may not contain the bodies of some of your dead coworkers) and made you care about it, by literally telling you NOT to care about it.
We're an odd bunch.