Worm monsters are a type of monsters that seclude in the ground. Revelations adds the following variants of worms.
Ice Worms are monsters that can be found in Glacier. They appear on ice tiles and shoot a line of three projectiles at the player before burrowing under the ice. If the player is standing on the ice, an Ice Worm may emerge directly underneath them, launching them into the air and potentially into other enemies or hazards. They do no contact damage.
Sand Worms appear in Tomb's sand rooms. They relocate to the sides of the player or directly above and below the player and charge. When they hit a wall they will relocate to somewhere else in the room and fire a small burst of tears at the player. If two Sand Worms collide while charging, they will both stop and quickly relocate before firing.
Tile Mongers hide in certain tiles in Trap Rooms. If there is an odd number of Tile Mongers in a room, one of the Tile Mongers will pop up and fire a sweep of tears towards the player before relocating. If there are an even number of Tile Mongers in a room, they will pick a pair, line up with each other and fire a line of tears between themselves for a long time before relocating once more.
A Tile Monger can be detected before he emerges by the shaking he causes on the tile's face. If the player happens to be standing on the said tile during this, the Tile Monger underneath relocates to a different tile to emerge from.