Life-Force Door

The Life-Force Door is a mysterious, swirling door from Starfox Adventures. It would very often block doorways to important places. The only way to get rid of them is to defeat some enemies to which represents guardians of the door.

The Life-Force Door consists of a bull-like skull and crossbones with entities that look like bird heads swirling around it. The number of those entities represents the number of enemies needed to defeat in order to get rid of the door. As soon as they are defeated, the door fades away.

Ultimate Story
For Ultimate Story 2: Dinosaur Planet, Fanfictiondreamer decided to make the Life-Force Doors into actually characters that can talk. This was done as a running gag of sorts. The doors tend to have names that start with D, such as Danno, Dannis, with them being completely made up names based on real names to make them more foreign. Each of the doors come off as snarky, arrogant, mocking anyone that would come near them and try but fail miserably to belittle anyone at they mock. To finish off this gag, as soon as the number of recommended enemies have been finished off, the Life-Force Doors fade away while shouting "Ahhh! My life is meaningless!!" which cracks up Fanfictiondreamer every time.