Swan Pond is an adventure map location, that gives a visiting hero +2 to luck until next battle. The Swan Pond also causes the visiting hero to lose all remaining movement points for the day. The latter feature makes the Swan Pond a popular strategic map object among map-makers. For example, it can be used in tight bottle necks to force heroes travel through it causing them to stop for a day.
In map editor, the Swan Pond is called Lake of Scarlet Swan in the help description.