Poison

Poison is a hazardous and harmful element that first appeared in Worms Armageddon. In Worms Armageddon, Worms World Party, and Worms 3D, poison can only be created by poisonous weapons or Sudden Death (although in Worms World Party and Worms 3D, a Wormpot mode called "Energy or Enemy" poisons every Worm on the landscape). However, in Worms 4: Mayhem and Worms: Ultimate Mayhem, poison can also be created by Oil Drums once destroyed (while in most Worms games they create fire instead when they explode), and in Worms Revolution, Worms Clan Wars, and Worms Battlegrounds, certain Physics Objects emit poison when sufficient force is applied.

Effects
When a worm is poisoned, its health slowly decreases every turn, usually 2 health points (5 in Worms 3D, and 10 in Worms 4: Mayhem) being taken away in-between turns. If a worm is not cured soon, it will not die, but its health will eventually be reduced to only 1 health point, making it extremely easy to kill. Worms can be cured from poison if they collect a health crate, use an Icarus Potion (Worms 4: Mayhem and Worms: Ultimate Mayhem only), use the Alien Abduction weapon on themselves (Worms 4: Mayhem and Worms: Ultimate Mayhem only), or drink Red Bull (Worms 3D only). It is also not recommended to use Alien Abduction on your own worm or other worms on your team (even if they are poisoned).

Poisonous Weapons
There aren't many poisonous weapons in the Worms series compared to standard weapons. The most powerful poisonous weapon is the Indian Nuclear Test, since it poisons every worm on the landscape, including your own worms. However, in Worms 3D, it is renamed "Nuclear Bomb" and only the worm who uses the weapon is not poisoned (while other worms on the user's team are poisoned), and in Worms Forts: Under Siege, it is renamed "Nuclear Strike" and does not poison any of the worms on the user's team. The Nuclear Strike is also the only poisonous weapon in Worms Forts: Under Siege, which is what makes the weapon unique in said game.

List of Poisonous Weapons
Here is the list of every poisonous weapon in the series.
 * Indian Nuclear Test/Nuclear Bomb/Nuclear Strike
 * Suicide Bomber
 * Skunk
 * Gas Canister
 * Blowpipe
 * Team Weapon (only if poison is enabled for the weapon)
 * Poison Strike
 * Gas Pump (renamed "Poison Gun" in Worms Revolution onward)
 * Whoopsie Cushion

Trivia

 * Although certain types of Mystery Crates give the worm extra health like health crates, they don't cure the worm if it's poisoned.