Insectoid Mandibles are a recurring type of enemy in "Buttville", the final level of the original Earthworm Jim video game. Like all the enemies in Buttville, they are Insectoids, the progeny and servants of Queen Slug-for-a-Butt.
Insectoid Mandibles tend to hide in the darkness, and are normally only visible by their glowing yellow eyes. They will sense when Jim gets too close, and will emerge to reveal themselves as long and worm-like. Despite being worm-like, they are nothing like our hero, with giant, extremely tough and dangerous pincer-like chelae mandibles.
These mandibles are among the few things in the Earthworm Jim video games which can actually do severe damage to Jim's Super Suit (other examples being Big Bruty and Mucus Phlegm Brain), and will bite the Super Suit in two halves in a single bite if Jim gets too close. Adding to their danger, they often lay in wait above remote and precarious platforms on which Jim also has to get onto in order to progress in the level.
The Insectoid Mandibles are resilient, but not invincible. It will take around a dozen hits with the Plasma Blaster to cause them to explode, or a single hit with a Mega Plasma or a single whip of Jim's worm head. However, be aware that when taking damage, and/or when killed, the Insectoid Mandibles will rain out corrosive acid blood in unexpected directions.