Gualicho or gualichu is an evil spirit or demon in the Mapuche mythology (Tehuelche culture).
By extension the term applied to an evil spell or charm, or a jinx ("It has Gualichu"). In this sense the word has evolved into gualicho and still survives in the local folklore of Chile and Argentina in the form of a noun and a verb (engualichar, to cast an evil spell on somebody or something).
Gualicho were described as spirits living in the rivers, woods, forests and there is no depiction of them.
Gualicho were not worshipped but feared. They were blamed for every disease or calamity, and all evil happenings were said to be caused by them. Gualicho could enter people's body or objects and then an exorcism had to be performed to expell them).