Peruvian Idiophone (Rattle): "Palo de Lluvia"

Rainsticks are usually made from any of several species of cactus. The cactuses, which are hollow, are dried in the sun. The spines are removed, then driven into the cactus like nails. Pebbles or other small objects are placed inside the rainstick, and the ends are sealed. A sound like falling water is made when the rainstick has its direction changed to a vertical position.

It seems likely that the origins of the rainstick as a musical instrument is the stick or tubular rattle.  Researchers at the turn of the century describe tubular rattles very similar to the rainstick which were made and used by the Cuna of Panama; the Colorado of Ecuador; the Macushí, Uachmiri, and Yauapery of northern Amazonia; and the Huichol of northern Mexico.  There are also wooden stick rattles filled with seeds or pebbles found archaeologically along the coast of Peru, but it is not clear whether these date from the Inca period or earlier (6000 B.C. - A.D. 1500).
 
Source:
https://study.com/academy/lesson/rain-sticks-history-purpose.html
https://sites.duke.edu/dumic/instruments/percussion/central-and-south-america/rain-stick/