Flood

Flood is a weapon that raises the water level and drowns Worms who stood close to the water.

In Worms Forts: Under Siege
The Flood weapon first appeared in Worms Forts: Under Siege. It's a default God Power weapon that slowly raises the water level higher and higher until the water level is very high. But a couple seconds after the water level's maximum height has been reached, the water level slowly "drains" back to its minimum height. Usually many Worms at the lower ground will be instantly killed from this weapon.

"This weapon will temporarily raise the water levels and washes away those not stood on higher grounds!" - description in the official website

In Worms 4: Mayhem & Worms: Ultimate Mayhem
However, the new Flood in Worms 4: Mayhem and Worms: Ultimate Mayhem is slightly different and it does the same effects as the Nuclear Bomb from Worms: The Director's Cut and Worms 2. It raises the water much less than the Flood in Worms Forts: Under Siege, but it stays like that for the rest of the round. Once this weapon is selected, the player's Worm holds a blue and orange colored umbrella, and when used, the Worm spins the umbrella and a thunderstorm cloud appears in the sky and starts raining heavily until a flash flood appears. Lightning is also seen and heard when the weapon is used. Also, if the player uses this weapon too many times, the water can eventually fill the whole landscape and kill everyone.

Usage
Once selected, simply press the Fire Button to activate the Flood.

Tips & Tricks

 * Although the Flood is a powerful weapon, you must save it for the best time and not use it right after you obtain the weapon. So only use Flood if a lot of enemy Worms are on low ground - that is the best time to use it.
 * In Worms Forts: Under Siege, although it's temporary, Flood raises the water a lot, so make sure that none of your Worms are anywhere near the water level before you use it. You're safe as long as your Worms are near their Forts.
 * Flood will also be the best weapon to use if all of your opponent's Worms are near the water level. This could result in your team's victory.
 * In Worms 4: Mayhem and Worms: Ultimate Mayhem, be aware that although the Flood doesn't raise the water level as high as the Flood in Worms Forts: Under Siege, the water raise is permanent for the whole round and you will have to fight on higher grounds, especially if this weapon is constantly used.
 * In Worms 4: Mayhem and Worms: Ultimate Mayhem, this weapon can also destroy Sentry Guns if they are on low ground. So if your opponent placed a Sentry Gun near the water level, the Flood will instantly destroy it.

Trivia

 * In Worms 4: Mayhem, the Flood is possibly a replacement of the Nuclear Bomb from Worms 3D, or more likely the Nuclear Bomb from Worms: The Director's Cut and Worms 2. The only difference is the Flood doesn't poison any Worms like the Nuke from Worms 3D does.
 * The Flood in Worms 4: Mayhem is also known as "Raindance".
 * In Worms 3 there is a card that raises the water level and then brings it back down, bringing down all worms and anything on the terrain.