Sponge bridge

In Pikmin Forever
Sponge bridges are obstacles in Pikmin Forever that consist of an immobile block of stone with a rounded bath sponge resting on top. Blue Pikmin that drink water can deposit water into a sponge bridge, causing it to expand. Once enough water is deposited in a sponge bridge, it will grow to a height that can make it useful as a bridge across a gap. The sponge constantly loses water, so it will not remain expanded for long before needing more. A sponge bridge can require anywhere from twenty to sixty water deposits to reach its maximum size; however, enemies such as a Watery Blowhogs can instantly expand the sponge to full capacity if lured over.