Freezing water

Cold Water is a a type of water that only appeared in Super Mario Galaxy in the Freezeflame Galaxy. Like regular water, it can be swum in; however, if Mario or Luigi stays in it for too long, they will lose one slice of their Health Meter. Therefore, to traverse it, an Ice Flower is required.

Cold Water's purpose is similar to lava in any fire-related Galaxy or level, except now in a ice-related Galaxy. They both serve as obstacles that can not be gone through without an Ice Flower. However, unlike Lava, it takes about 2 seconds in cold water for Mario and Luigi to take damage. Also, when Mario or Luigi take damage, they will not move uncontrollably, unlike Lava.

There is a glitch that allows Mario or Luigi to traverse cold water without using an Ice Flower or taking damage over time. Usually, Mario or Luigi can not jump in water unless they are next to land. However, a second player utilizing the Star Cursor can make Mario or Luigi jump, even if they are in water. Jumping out of the cold water immediately cancels the code for taking damage in water. This means that if the second player makes Mario or Luigi jump consecutively within around 2 seconds of each jump, Mario or Luigi will safely be able to swim across cold water.