"Chupacabras" means "goat sucker" in Spanish. It refers to the mythical beast who drained livestock of their blood. The creature was first mentioned in Puerto Rico, but then sightings were reported all over Latin America.
The Spanish quote at the beginning - "Cuide su rebaño, nunca deje su lado. Cuide su sangre, el chupacabra tiene hambre." - translates to: "Take care of your flock, never leave their side. Take care of your blood, the chupacabra is hungry."
When Wu pulls the tarp off the victims at the first crime scene, 'NWN2POLY' is spray painted in yellow paint on the street. This is a reference to the role playing video game Neverwinter Nights 2.
The opening quote for this episode was the first to be in Spanish since "El Cucuy", but unlike that episode, there was no translation given.
The opening quote roughly translated means: "Cuide su rebaño, nunca deje su lado. Cuide su sangre, el Chupacabra tiene hambre." "Take care of your flock, never leave their side. Watch your blood, for the Chupacabra is hungry."