In some areas infused with cold energy, particularly where icy parts of the Elemental Chaos erupt into the world, a strange form of ice crawls toward any kind of heat. Living creatures that stand on the ice are slowly drained of life.
Effect: Any creature that starts and ends its turn in any square of creeping ice takes 5 cold damage per tier.
Usage: Creeping ice is a great tool to persuade the characters to move around an encounter area, particularly if you place it in spots where characters who have ranged attacks are likely to position themselves.
Published in Dungeon Master's Guide 2, page(s) 58.