In the 60s, DARPA successfully genetically engineered a cobra/stingray hybrid, issuing it to the Navy SEALs as a replacement for the M3 Grease Gun. 

The intended use case was filling VC tunnels with truckloads of salt water and sending in the "Cobrays" in using buckets to finish the job. 

The SEALs quickly discovered that they could simply throw them at the enemy. If the venomous fangs didn't get them, the painful stings would lead to a quick surrender. Occasionally, a Charlie would get "Steve Irwined."

A muzzle device was developed for both the M79 and the China Lake, used with 40mm blanks, allowed them to be launched from a safe range of up to 150 yards.

Overall, one of DARPA's more successful endeavors.

Way better than the Internet.