Roswell Conspiracies: Aliens, Myths and Legends (1999)

S1E10 Chupacabra

Unusual actions from cattle in South America lead Rinaker to dispatch Nick and Sh'lainn on a mission to uncover the truth behind the elusive Chupacabra. However, they soon stumble upon shocking revelations that expose a connection to an alien massacre, orchestrated by a shapeshifter masquerading as an Alliance agent, along with clues about the fabled city of the Dark Empire.