Now, the probable locations to find Chupacabra are South of Perdido, South of Sepulcro, Casa Madrugada, and Mesa del Sol, all of which are in Mexico. When you have come near to this mystical creature, a royal blue circle will notify you of its presence in the area.
You can refer to this video guide below on how to locate and kill this creature and rank up as Undead Hunter. You will also unlock the trophy Chupathingy when you kill this creature.
Now, when you are near Unicorn, you don’t get any notification, its near the area where you can see the three horses in the map below.
Map courtesy PS3 Trophies @ amricardo
Now follow this video guide for the exact location of the unicorn and unlock Fan Service trophy.