EASTER ISLAND MAT'A 'A HAVE defied classification for over a century. These objects are most commonly interpreted as "spearpoints" that were hafted to a handle and used in combat (e.g., Metraux 1940: 166-7).
Bollt, Robert; Clark, Jesse E.; Fisher, Philip R.; and Yoshida, Hirosato K.
"An Experiment in the Replication and Classification of Easter Island Mata'a,"
Rapa Nui Journal: Journal of the Easter Island Foundation: Vol. 20
, Article 6.
Available at: https://kahualike.manoa.hawaii.edu/rnj/vol20/iss2/6