Infested Worms are a particularly annoying enemy. When they appear it can cause serious trouble. One variety can and will appear at random, and vomit up a large swarm of Parasites that can quickly envenom a player beyond all hope. the other variety is specific to the Mini-Boss Menoetes, and therefore, Easy Company.
These are the arguably more common of the two worm subtypes, and are also deadlier. Venom Worms will randomly unburrow unleashing a huge number of Parasites onto nearby marines. Parasites themselves have the lowest threat value, so marines will target any other hostile unit before them. As a result, given its moderately high health and by-default higher threat, the worm itself will end up drawing the attention of player's ai. The best response is to begin moving as soon as you hear the tell-tale noise of a worm unburrowing. With any luck your Shields will absorb the brunt of the hits, therefore protecting you from the ailments.
Classes with fast response Area of Effect skills can kill all if not most of the parasites before they cause any significant harm. The Nano-Medic's Mindblast, Marksman's Monofilament Cartridge, and Combat Rifleman's Grenades will easily dispatch the creatures. Likewise, support skills such the Recon's Escape, the Assault's Stun, and Rifleman's Sonic Traps can be used to protect allies, rather than kill the threat immediately.
Regardless of player actions, these Venom Worms and their parasites give an unusually high amount of in game experience when killed. As a result to competent players or organized teams they are essentially free experience, where as with poor or inexperienced players they can be a deathtrap. Venom Worms are quite rare on lower difficulties, but become more common as Squad Rating and Game Mode increase.
These worms will only appear when Menoetes is alive. As the beast rampages about the map, it sends forth infested worms that explode on impact. These worms will inflict heavy damage, and almost always cripple anything unfortunate enough to be underneath them on detonation. These worms attack more and more frequently as difficulty increases. They will only stop once Menoetes has been slain.