According to NBC San Diego, officers entered the house of 32-year-old Assif Mayar to find a large alligator guarding 34 pounds of dried processed marijuana.
Sgt. JD Nelson said: "Instead of a guard dog you had a guard alligator. It's a little unnerving to have a live alligator that opens its mouth when you walk in the room."
The five-foot Caiman alligator, named Mr Teeth, is said to be one of the largest that Animal Control has ever had to collect.
When determining the age of the animal, Nelson explained: "[Mayar] said he got it to commemorate the death of Tupac Shakur so that's how we knew it was approximately 16 years old."
Mr Teeth was taken to the Oakland Zoo where he is recovering and will be in quarantine for 30 days. Zoo officials described his condition as "very sick".
Neighbours admitted that they had no idea an alligator was inside the house Mayar shared with his wife and young son.
One said: "It doesn't belong in a neighbourhood with little kids and there are a lot of little kids. If that thing got out it could be really dangerous."
Caimans are usually from South and Central America and require a lot of care.