Pits created by freezing water and then digging out the ice gradually and randomly fill back in with water. But if you then try to frost walk on them (with water walking boots and white dragon scale mail), you get the following: “The water crackles and freezes under your weight. The ice breaks under your weight! You fall into your pit!” creating the pit anew on the space.

Water walking boots do not sink in water. They stay on top of the surface and can be picked up by something else that has water walking.

Object property “frost walker”, which only generates on boots. When worn, lava cools into solid floor and water freezes into ice in a radius 1 around the wearer. Optional if they unfreeze afterwards. Alternatively, make this an artifact pair of water walking boots.

Polymorphing a crocodile corpse makes fireproof water walking boots instead of fireproof low boots.

Water walking boots give you the same extra speed as speed boots if you are standing on water or a fountain.