Venom Grub

Venom Grubs are the two (possibly related, or even the same) species, one encountered by the First Doctor, another was told of to the Ninth Doctor.

Vortis Venom Grubs
Venom Grubs of Vortis were the living weapons of the Zarbi, at that time controlled by the Animus, in their war against the Menoptra. They measured approximately two meters in length and half a meter high. The grubs ejected jets of venom from a pointed orifice located beneath their eyes. (DW: The Web Planet)



Slitheen Venom Grubs
The Slitheen Venom Grubs are a Venom Grub species used by the Slitheen Family. These Venom Grubs are used to dispose of unwanted members. Blon claimed that if she didn't follow the criminal activities of the rest of the family, she would have been fed to the Venom Grubs. (DW: Boom Town)


 * If these two types of Venom Grub are related, than it may mean the Slitheen had intergalactic capabilties. However, venom grubs may simply have evolved on more than one world. As to the Slitheen family using the grubs against their own family members, Blon may well have lied to the Doctor in order to gain his sympathy.