Spawg

A Spawg derives its name from its resemblance to a Pit Bull Terrier, although 30% larger, and the fact that it secretes and uses a paralyzing venom in its self-defense. These strong and highly trainable animals are sought after as personal protection and for harvesting the Spawg's venom. They are loyal to masters who treat them with respect and yet protectively viscious and aggressive when necessary.
They are also bred for use in the illegal dogfighting trade, where the venom sac from the spawg is removed, and are thus mistaken for the pit bulls they resemble. The dogfighting trade is not known for its moral or kind treatment of fighting dogs, Spawgs with their venom sacs intact are still banned from such fights. Thus more unscrupulous handlers will attempt to pass off the modified Spawg because they tend to be more successful than any particular dog breed.
An extract of Spawg venom can be produced by bringing the contents of Spawg venom sacs to a boil for 5 minutes. This procedure removes impurities that may have been introduced in the extraction process and too reduce the venom to a concentrated form. This extract is then sold to medical practioners when patients need to be immobilized for a short period of time. Medicinal use is a small market. Multiple doses can be issued to lengthen the effect, but too large a dose can result in the recipients death. A significant black market exists for the use and creation of Spawg venom and this by far has created the largest demand and supply. The venom has a shelf life of only 30 days before becoming ineffective
Spawg take a full year to mature and produce venom. Breeders will maintain a herd of Spawg only until their venom sacs mature and are removed. The Spawg are then sold to unscrupulous dog fighters or are outright euthenized, their primary value having been exhausted upon removal of the venom sac.