Worms are small, pale, pink worms with no arms and no legs. The have a small, wiggling bodies, and the only other feature on their bodies is their mouth, which has a pink tongue and small white teeth in it.
Worms first appear in level 10 of Cave Chaos 2, two-thirds of the way through the game. In a level that worms appear in, one to five worms will be dropped from the top of the screen on to a block. Worms will then slowly squirm in a random direction. However, although they squirm slowly, they can surprise the player by their ability to jump incredibly quickly and high. When the player comes near to a worm, the worm will begin to squirm quickly toward them, and once they are close enough the worm will often use their aforementioned leap to dig into the miner's ear.
Worms are usually placed so that they are impossible to avoid touching them, in order that the player doesn't cheat and play the level without turning into a beast. However, in level 10, if the player starts at the checkpoint, they can sometimes move up close to the worms and then jump over them, finishing the rest of the level as a normal miner. Worms will continually follow the player if they are close enough, and continue doing so until the player gets a certain distance away from the worms.
Worms are a hazard because they possess the ability to transform the player into a hideous beast. When a miner touches a worm, the worm will immediately jump into the miner's ear, and begin transforming the miner into the beast.
First, half of the miner's body will turn into beast-form. The half of the body depends on which side the worm jumped into, because the transformation will begin on the opposite side (eg. If the worm jumps into the right ear, the transformation will start on the left.) When the miner is transforming, the player will momentarily lose control over the miner and will not be able to move him. The process does not stop the platforms from falling though.
The final product of this transformation is the miner turned into a beast that is all white, has long ears, and has lumps all over its body. The worm-ridden miner will immediately begin running forward very fast, faster than the miner can run normally, and even faster than the bats can put down platforms. This running is uncontrollable, and the player will sometimes have to double back on itself, or find something to block its way so that it doesn't run off the unfinished platform. In addition to the increased speed, the beast-form of the miner can jump much higher too. Some normally inaccessible platforms can be reached using the beast's super jump.
Once the player has reached the end of the level and touches the finish lantern in beast form, the beast will stop and start vomiting an olive-green coloured liquid (possibly a product of trying to get rid of the worm's control). By the beginning of the next level, the miner is back to normal.
When in beast form the player will often run too fast for the bats to put down platforms, causing them to run off the edge. Instead the player can come to a pause by rapidly pressing theand keys over and over again. This will cause the beast to stay in a small area for as long as needed.