Filler is a skill that can be given to a lemming in Lemmings 2: The Tribes. A filler pours a fixed amount of liquid from a bucket held above its head. This liquid moves along the terrain, falling to lower ground whenever possible, until it reaches a point where it cannot travel any further. The liquid then solidifies and becomes part of the terrain on the level. The filler may be used to block pits (which in many cases are designed specifically for use of the filler), or even cover bodies of water, so that lemmings don't fall in.