The Kraathatrogon are a species of gigantic worm-like creatures from Dimension X. They produce Mutagen and are vulnerable to salt.
The Manhattan Project - The Kraang bring several worms to Earth to extract their mutagen. The Kraathatrogons travel through old subway systems, and their enormous size causes tremors with effects similar to earthquakes. When Casey Jones attempts to stop them, one swallows him. Donatello and April O'Neil kill it with salt. later April and Casey ride a worm to battle and Tiger Claw gets eaten, the Kraathatrogon is sent to the 80's turtles dimension.