el chupacabra
I don’t go in for monsters or aliens, but I just love this word. I like it in Spanish and I like it in English (“goat sucker”).
Also cool:
ABE – Anomalous Biological Entities
and bunyip:
A bunyip is a legendary spirit or creature of the Australian Aborigine. Bunyips haunt rivers, swamps, creeks and billabongs. Their main goal in life is to cause nocturnal terror by eating people or animals in their vicinity. They are renowned for their terrifying bellowing cries in the night and have been known to frighten Aborigines to the point where they would not approach any water source where a bunyip might be waiting to devour them.