Huge, hideous white grub worms created by Dr. Viper out of the five kats bitten and converted by Dr. Harley Street, including rookie Enforcer Gray Taylor. Taylor and the four converted escaped convicts were transformed by Viper into giant grub worms suitable for digging through the earth so that they, and the scarab Viper turned Street into, could tunnel into the Megakat Thermonuclear Plant and rupture its reactor core, causing a meltdown which would allow Viper to turn Megakat City into “Viper City,” a toxic radioactive wasteland over which he would rule.

The worms were heavily armored and impervious to most weapons. The SWAT Kats were able to simultaneously kill them and prevent the nuclear reactor from overheating by flooding the power plant with water from Megakat Tower. Trapped inside the flooding cooling tower, the grubs, incapable of swimming, quickly sank and drowned.