In a Phaser game, I was unknowingly overriding a method of a parent class. It must've been Phaser.Group or Phaser.Sprite that my class was extending, I was calling destroy() on it without realising I was calling the parent class' method too and was baffled about why shit wasn't working. Found out maybe two days later and changed the method 'destroy()' in my class to 'pokeItWithAStick()'. This was at a previous job, but I'm mostly sure that it stays that way in the codebase three years later.