Water

Water is the deadliest hazard in Worms. If a Worm walks, falls, or gets knocked into the water, they will instantly die from drowning. Water can be used to your advantage (by using the water to kill an opponent, such as knocking an enemy into the water), but it could also be quite bad for you (obvious problems include your opponent knocking you into the water and flubbed maneuvering across the map). Walking into the water is a terrible idea - Worms is not a fishing game, so don't even think about doing it!

Water has many uses. You obviously can knock an opponent into the water, but you can also use the water to get rid of hazards, such as Mines, by knocking it into the water with a Baseball Bat. You can even use a Nuclear Bomb or Indian Nuclear Test to raise the water and drown the enemy. That is the best use of water, when most (if not all) enemy Worms are near the water level. Water is more dangerous than any weapon, and this may be why the Nuke is one of the series' most powerful weapons.

Dynamic Water
Dynamic Water is a type of water introduced in Worms: Revolution that appears on the stage above the natural water of the stage. It is affected by physics and gravity. Unfortunately it can't be used as an instant kill trap or disabling other traps, but Worms who stay in dynamic water gradually lose health each turn. It can also displace other Worms as well.

Water weapons (weapons which create dynamic water) were introduced in Worms: Revolution, and made a big change in the gameplay of Worms.

Appearance
In the first generation Worms games, there are different water appearances. For example, the Hell Theme replaces water with fire/lava (the effects of drowning are always the same, different themes only change the appearance of the water). However, in Worms 2, there is only water, no theme-replacements such as hell-fire, though the water comes in different colors, though. But even that was disabled for the rest of the second generation Worms, and for most of the later Worms games, the water is always blue, no matter what theme it is. Also, the commentary panel shows up when a Worm drowns (in any Worms game).