supertux/data/images/objects/bullets/firebullet.sprite

(supertux-sprite
 (action
  (hitbox 2 2 12 12)
  (fps 20)
  (images "fire_bullet-0.png"
   "fire_bullet-1.png"
   "fire_bullet-2.png"
   "fire_bullet-3.png")
 )
)