"Science, my friends, science!"
Dr. Gerbil is mad scientist fronting as a vaccuum salesman. He is the antagonist in the episode Human Habitrail.
Developer of a variety of food and cosmetics, his belief in animal freedom and implied history as a laboratory animal led him to experiment on human subjects. He appears to be extremely narcissistic, proven by the self-dedicated theme park built in the elaborate series of tunnels in his underground home. Concurrently, he believes that by trapping the Bagges he is freeing Courage from ownership. So while the results of his research are certainly inhumane, he may not be motivated by vengeance alone.