supertux/data/images/objects/unstable_tile/unstable_tile.sprite

(supertux-sprite
  (action
    (name "normal")
    (images 
      "normal.png"
    )
  )
  (action
    (name "shake")
    (fps 20)
    (images 
      "crumbling-0.png"
      "crumbling-1.png"
      "crumbling-0.png"
      "crumbling-1.png"
      "crumbling-0.png"
      "crumbling-1.png"
      "crumbling-0.png"
      "crumbling-1.png"
      "crumbling-0.png"
      "crumbling-1.png"
    )
  )
  (action
    (name "fall-down")
    (fps 1)
    (images 
      "normal.png"
    )
  )
)