In the Worms series, players use Worms to play the game and annihilate opponents. They are the only playable characters in the series. While mostly pink in color like real Worms, some games allow customization of the skin color.
The Worms in the series appear to be far more humanoid than real-life earthworms, and are also very cartoon-ish. They have large eyes, small, floating eyebrows, a mouth (with teeth), large, floating hands with only four fingers (with no fingernails or arms connected to their hands), and a tail. They also seem to have a skeleton, but still referred to as invertebrates in the games. They also do not have a nose or ears and they appear to be limbless.
Originally, the Worms were less cartoonish, darker of color and more fierce-looking. They also did have a nose and arms. Although, this was not visible in the gameplay due to the pixelated graphics because they're small.
The Worms usually speak with a high-pitched voice. Although, the player can customize this in most of the games.
It is worth noting that they cannot swim, and avoid water whenever necessary.
- At first, they appeared to be quite weird compared to real life earthworms. They had a humanoid, muscular build in their upper body, a defined neck and a long bottle shaped nose. The worms would slowly change over the years to look like we know them today.
- In the cover art of Worms: The Director's Cut, the worm looked more ugly than in Worms Reinforcements, Worms United and the first Worms game, as its body was even more defined, it had an even longer nose, crooked teeth, a long tongue and a furious expression.
- In the cover art of Worms 2 and Worms Armageddon, they started to look a little more like the current worms, but not quite. Now their bodies were no longer defined and muscular, instead short and squished, as how the worms standardly look. However, they still have noses, now small and squished noses showing their nostrils, instead of the bottle-shaped nose, and the humanoid arms, while shorter, are still present.
- In the cover art of Worms World Party, the picture was better than before. The noses are now gone all together, but it's still not quite there. The arms are still attached, albeit even shorter now, and some have more realistic human teeth. When you see the back group of the worms, they look similar to them in tribute mode.
- Worms 3D was the first game to have the worms completely as we know them today, with short, squished and chubby light pink bodies, no noses or attached arms, appear limbless, floating eyebrows and hands, and a large, white toothy, cartoony smile.
- In Worms Revolution, the worms were given a slight redesign, giving them a different body shape. They were also seperated into different Classes. The Soldier retains the original look, the Scout is slightly smaller than the other classes, the Scientist is a bit small but bigger than the Scout, and has a large brain, and the Heavy is big and bulky, with a different eye shape compared to the other three.
- In Worms W.M.D., the worms changed their style. They now look more mean-looking, have dotted eyes and sharp teeth, and a toothy grin. They still appear limbless, though their heads are slightly flatter than before.