An animal used for experimentation in a laboratory, usually for experiments involving new medicine, other items needed to be deemed safe before use on humans, or other scientific studies. These animals tend to be small mammals, like rats and mice.
Being a lab animal is usually a backstory for sparkledogs. It explains their general weirdness and strange colors caused by "genetic experimentation" and wings.
1. The medicine was tested on the lab rats before it was used on humans.
Person 1: But my furry isn't a sparkledog! She's an escaped lab animal!
Person 2: *sigh* Noob.