Feather minigame
From Celeste Wiki
The Feather minigame is a minigame which appears in Chapter 4 and 6.
The minigame begins with a yellow feather appearing onscreen and the screen darkening. Holding space(confirm please) makes the feather rise, and the feather sinks slowly when no key is pressed. After a little while, a box appears. When the feather is outside the box, it flutters rapidly. The minigame ends when the feather is kept in the box for long enough(don't know how long).