What type of cartridge is known for containing a pyrotechnic projectile in a plastic case?

The bird scare cartridge is specifically designed to contain a pyrotechnic projectile, which is used to create loud noises or visual effects to scare birds and other wildlife away from certain areas, such as airports or agricultural fields. The plastic casing of this cartridge typically houses the pyrotechnic materials safely, ensuring that they ignite appropriately when fired.

This type of cartridge is not used for traditional firearm applications, but instead serves a particular purpose tied to wildlife management. The other options do not possess the same characteristics: slug cartridges typically contain solid projectiles for hunting or defense; double-ot buckshot consists of multiple small pellets for wider spread but lacks a pyrotechnic feature; and a training dummy cartridge is designed for safety and does not contain a live projectile at all. Thus, the unique function and design of the bird scare cartridge makes it the correct choice for this question.